From 9e809d15d6b692fa061d74be7aaab1c79f6784b8 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Wed, 14 Feb 2018 18:59:23 +0100
Subject: x86/entry: Reduce the code footprint of the 'idtentry' macro
Play a little trick in the generic PUSH_AND_CLEAR_REGS macro
to insert the GP registers "above" the original return address.
This allows us to (re-)insert the macro in error_entry() and
paranoid_entry() and to remove it from the idtentry macro. This
reduces the static footprint significantly:
text data bss dec hex filename
24307 0 0 24307 5ef3 entry_64.o-orig
20987 0 0 20987 51fb entry_64.o
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180214175924.23065-2-linux@dominikbrodowski.net
[ Small tweaks to comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/calling.h | 11 ++++++++++-
arch/x86/entry/entry_64.S | 18 ++++++++----------
2 files changed, 18 insertions(+), 11 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index dce7092ab24a..196b6103edf6 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -97,7 +97,7 @@ For 32-bit we have the following conventions - kernel is built with
#define SIZEOF_PTREGS 21*8
-.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax
+.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax save_ret=0
/*
* Push registers and sanitize registers of values that a
* speculation attack might otherwise want to exploit. The
@@ -105,8 +105,14 @@ For 32-bit we have the following conventions - kernel is built with
* could be put to use in a speculative execution gadget.
* Interleave XOR with PUSH for better uop scheduling:
*/
+ .if \save_ret
+ pushq %rsi /* pt_regs->si */
+ movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */
+ movq %rdi, 8(%rsp) /* pt_regs->di (overwriting original return address) */
+ .else
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
+ .endif
pushq \rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq \rax /* pt_regs->ax */
@@ -131,6 +137,9 @@ For 32-bit we have the following conventions - kernel is built with
pushq %r15 /* pt_regs->r15 */
xorq %r15, %r15 /* nospec r15*/
UNWIND_HINT_REGS
+ .if \save_ret
+ pushq %rsi /* return address on top of stack */
+ .endif
.endm
.macro POP_REGS pop_rdi=1 skip_r11rcx=0
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8971bd64d515..77edc2390868 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -875,12 +875,8 @@ ENTRY(\sym)
pushq $-1 /* ORIG_RAX: no syscall to restart */
.endif
- /* Save all registers in pt_regs */
- PUSH_AND_CLEAR_REGS
- ENCODE_FRAME_POINTER
-
.if \paranoid < 2
- testb $3, CS(%rsp) /* If coming from userspace, switch stacks */
+ testb $3, CS-ORIG_RAX(%rsp) /* If coming from userspace, switch stacks */
jnz .Lfrom_usermode_switch_stack_\@
.endif
@@ -1130,13 +1126,15 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1
#endif
/*
- * Switch gs if needed.
+ * Save all registers in pt_regs, and switch gs if needed.
* Use slow, but surefire "are we in kernel?" check.
* Return: ebx=0: need swapgs on exit, ebx=1: otherwise
*/
ENTRY(paranoid_entry)
UNWIND_HINT_FUNC
cld
+ PUSH_AND_CLEAR_REGS save_ret=1
+ ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
rdmsr
@@ -1181,12 +1179,14 @@ ENTRY(paranoid_exit)
END(paranoid_exit)
/*
- * Switch gs if needed.
+ * Save all registers in pt_regs, and switch GS if needed.
* Return: EBX=0: came from user mode; EBX=1: otherwise
*/
ENTRY(error_entry)
- UNWIND_HINT_REGS offset=8
+ UNWIND_HINT_FUNC
cld
+ PUSH_AND_CLEAR_REGS save_ret=1
+ ENCODE_FRAME_POINTER 8
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@@ -1577,8 +1577,6 @@ end_repeat_nmi:
* frame to point back to repeat_nmi.
*/
pushq $-1 /* ORIG_RAX: no syscall to restart */
- PUSH_AND_CLEAR_REGS
- ENCODE_FRAME_POINTER
/*
* Use paranoid_entry to handle SWAPGS, but no need to use paranoid_exit
--
cgit v1.2.1
From ced5d0bf603fa0baee8ea889e1d70971fd210894 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Wed, 14 Feb 2018 18:59:24 +0100
Subject: x86/entry/64: Use 'xorl' for faster register clearing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
On some x86 CPU microarchitectures using 'xorq' to clear general-purpose
registers is slower than 'xorl'. As 'xorl' is sufficient to clear all
64 bits of these registers due to zero-extension [*], switch the x86
64-bit entry code to use 'xorl'.
No change in functionality and no change in code size.
[*] According to Intel 64 and IA-32 Architecture Software Developer's
Manual, section 3.4.1.1, the result of 32-bit operands are "zero-
extended to a 64-bit result in the destination general-purpose
register." The AMD64 Architecture Programmer’s Manual Volume 3,
Appendix B.1, describes the same behaviour.
Suggested-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180214175924.23065-3-linux@dominikbrodowski.net
[ Improved on the changelog a bit. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/calling.h | 16 ++++++------
arch/x86/entry/entry_64_compat.S | 54 ++++++++++++++++++++--------------------
2 files changed, 35 insertions(+), 35 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 196b6103edf6..5d10b7a85cad 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -117,25 +117,25 @@ For 32-bit we have the following conventions - kernel is built with
pushq %rcx /* pt_regs->cx */
pushq \rax /* pt_regs->ax */
pushq %r8 /* pt_regs->r8 */
- xorq %r8, %r8 /* nospec r8 */
+ xorl %r8d, %r8d /* nospec r8 */
pushq %r9 /* pt_regs->r9 */
- xorq %r9, %r9 /* nospec r9 */
+ xorl %r9d, %r9d /* nospec r9 */
pushq %r10 /* pt_regs->r10 */
- xorq %r10, %r10 /* nospec r10 */
+ xorl %r10d, %r10d /* nospec r10 */
pushq %r11 /* pt_regs->r11 */
- xorq %r11, %r11 /* nospec r11*/
+ xorl %r11d, %r11d /* nospec r11*/
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx*/
pushq %rbp /* pt_regs->rbp */
xorl %ebp, %ebp /* nospec rbp*/
pushq %r12 /* pt_regs->r12 */
- xorq %r12, %r12 /* nospec r12*/
+ xorl %r12d, %r12d /* nospec r12*/
pushq %r13 /* pt_regs->r13 */
- xorq %r13, %r13 /* nospec r13*/
+ xorl %r13d, %r13d /* nospec r13*/
pushq %r14 /* pt_regs->r14 */
- xorq %r14, %r14 /* nospec r14*/
+ xorl %r14d, %r14d /* nospec r14*/
pushq %r15 /* pt_regs->r15 */
- xorq %r15, %r15 /* nospec r15*/
+ xorl %r15d, %r15d /* nospec r15*/
UNWIND_HINT_REGS
.if \save_ret
pushq %rsi /* return address on top of stack */
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index fd65e016e413..364ea4a207be 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -85,25 +85,25 @@ ENTRY(entry_SYSENTER_compat)
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
- xorq %r8, %r8 /* nospec r8 */
+ xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
- xorq %r9, %r9 /* nospec r9 */
+ xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
- xorq %r10, %r10 /* nospec r10 */
+ xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
- xorq %r11, %r11 /* nospec r11 */
+ xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp (will be overwritten) */
xorl %ebp, %ebp /* nospec rbp */
pushq $0 /* pt_regs->r12 = 0 */
- xorq %r12, %r12 /* nospec r12 */
+ xorl %r12d, %r12d /* nospec r12 */
pushq $0 /* pt_regs->r13 = 0 */
- xorq %r13, %r13 /* nospec r13 */
+ xorl %r13d, %r13d /* nospec r13 */
pushq $0 /* pt_regs->r14 = 0 */
- xorq %r14, %r14 /* nospec r14 */
+ xorl %r14d, %r14d /* nospec r14 */
pushq $0 /* pt_regs->r15 = 0 */
- xorq %r15, %r15 /* nospec r15 */
+ xorl %r15d, %r15d /* nospec r15 */
cld
/*
@@ -224,25 +224,25 @@ GLOBAL(entry_SYSCALL_compat_after_hwframe)
pushq %rbp /* pt_regs->cx (stashed in bp) */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
- xorq %r8, %r8 /* nospec r8 */
+ xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
- xorq %r9, %r9 /* nospec r9 */
+ xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
- xorq %r10, %r10 /* nospec r10 */
+ xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
- xorq %r11, %r11 /* nospec r11 */
+ xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp (will be overwritten) */
xorl %ebp, %ebp /* nospec rbp */
pushq $0 /* pt_regs->r12 = 0 */
- xorq %r12, %r12 /* nospec r12 */
+ xorl %r12d, %r12d /* nospec r12 */
pushq $0 /* pt_regs->r13 = 0 */
- xorq %r13, %r13 /* nospec r13 */
+ xorl %r13d, %r13d /* nospec r13 */
pushq $0 /* pt_regs->r14 = 0 */
- xorq %r14, %r14 /* nospec r14 */
+ xorl %r14d, %r14d /* nospec r14 */
pushq $0 /* pt_regs->r15 = 0 */
- xorq %r15, %r15 /* nospec r15 */
+ xorl %r15d, %r15d /* nospec r15 */
/*
* User mode is traced as though IRQs are on, and SYSENTER
@@ -298,9 +298,9 @@ sysret32_from_system_call:
*/
SWITCH_TO_USER_CR3_NOSTACK scratch_reg=%r8 scratch_reg2=%r9
- xorq %r8, %r8
- xorq %r9, %r9
- xorq %r10, %r10
+ xorl %r8d, %r8d
+ xorl %r9d, %r9d
+ xorl %r10d, %r10d
swapgs
sysretl
END(entry_SYSCALL_compat)
@@ -358,25 +358,25 @@ ENTRY(entry_INT80_compat)
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
- xorq %r8, %r8 /* nospec r8 */
+ xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
- xorq %r9, %r9 /* nospec r9 */
+ xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
- xorq %r10, %r10 /* nospec r10 */
+ xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
- xorq %r11, %r11 /* nospec r11 */
+ xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp */
xorl %ebp, %ebp /* nospec rbp */
pushq %r12 /* pt_regs->r12 */
- xorq %r12, %r12 /* nospec r12 */
+ xorl %r12d, %r12d /* nospec r12 */
pushq %r13 /* pt_regs->r13 */
- xorq %r13, %r13 /* nospec r13 */
+ xorl %r13d, %r13d /* nospec r13 */
pushq %r14 /* pt_regs->r14 */
- xorq %r14, %r14 /* nospec r14 */
+ xorl %r14d, %r14d /* nospec r14 */
pushq %r15 /* pt_regs->r15 */
- xorq %r15, %r15 /* nospec r15 */
+ xorl %r15d, %r15d /* nospec r15 */
cld
/*
--
cgit v1.2.1
From d1c99108af3c5992640aa2afa7d2e88c3775c06e Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@amazon.co.uk>
Date: Mon, 19 Feb 2018 10:50:56 +0000
Subject: Revert "x86/retpoline: Simplify vmexit_fill_RSB()"
This reverts commit 1dde7415e99933bb7293d6b2843752cbdb43ec11. By putting
the RSB filling out of line and calling it, we waste one RSB slot for
returning from the function itself, which means one fewer actual function
call we can make if we're doing the Skylake abomination of call-depth
counting.
It also changed the number of RSB stuffings we do on vmexit from 32,
which was correct, to 16. Let's just stop with the bikeshedding; it
didn't actually *fix* anything anyway.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: arjan.van.de.ven@intel.com
Cc: bp@alien8.de
Cc: dave.hansen@intel.com
Cc: jmattson@google.com
Cc: karahmed@amazon.de
Cc: kvm@vger.kernel.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Link: http://lkml.kernel.org/r/1519037457-7643-4-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_32.S | 3 +--
arch/x86/entry/entry_64.S | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 16c2c022540d..6ad064c8cf35 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -252,8 +252,7 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
- /* Clobbers %ebx */
- FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
+ FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 77edc2390868..7a53879ec689 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -364,8 +364,7 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
- /* Clobbers %rbx */
- FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
+ FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */
--
cgit v1.2.1
From 0e34d226342c27c4f96138b211547d423e4be8a1 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:08 +0100
Subject: x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper
function
The PUSH_AND_CLEAR_REGS macro is able to insert the GP registers
"above" the original return address. This allows us to move a sizeable
part of the interrupt entry macro to an interrupt entry helper function:
text data bss dec hex filename
21088 0 0 21088 5260 entry_64.o-orig
18006 0 0 18006 4656 entry_64.o
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-2-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7a53879ec689..b0ae0c3e3815 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -525,6 +525,14 @@ END(irq_entries_start)
*
* Entry runs with interrupts off.
*/
+ENTRY(interrupt_entry)
+ UNWIND_HINT_FUNC
+
+ PUSH_AND_CLEAR_REGS save_ret=1
+ ENCODE_FRAME_POINTER 8
+
+ ret
+END(interrupt_entry)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
@@ -536,8 +544,7 @@ END(irq_entries_start)
call switch_to_thread_stack
1:
- PUSH_AND_CLEAR_REGS
- ENCODE_FRAME_POINTER
+ call interrupt_entry
testb $3, CS(%rsp)
jz 1f
--
cgit v1.2.1
From 2ba6474104a1132c4af9f6dc42c6bfe3ca71f8c7 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:09 +0100
Subject: x86/entry/64: Move ENTER_IRQ_STACK from interrupt macro to
interrupt_entry
Moving the switch to IRQ stack from the interrupt macro to the helper
function requires some trickery: All ENTER_IRQ_STACK really cares about
is where the "original" stack -- meaning the GP registers etc. -- is
stored. Therefore, we need to offset the stored RSP value by 8 whenever
ENTER_IRQ_STACK is called from within a function. In such cases, and
after switching to the IRQ stack, we need to push the "original" return
address (i.e. the return address from the call to the interrupt entry
function) to the IRQ stack.
This trickery allows us to carve another .85k from the text size (it
would be more except for the additional unwind hints):
text data bss dec hex filename
18006 0 0 18006 4656 entry_64.o-orig
17158 0 0 17158 4306 entry_64.o
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-3-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 56 ++++++++++++++++++++++++++++++++---------------
1 file changed, 38 insertions(+), 18 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index b0ae0c3e3815..7a6ae19962ec 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -448,9 +448,19 @@ END(irq_entries_start)
*
* The invariant is that, if irq_count != -1, then the IRQ stack is in use.
*/
-.macro ENTER_IRQ_STACK regs=1 old_rsp
+.macro ENTER_IRQ_STACK regs=1 old_rsp save_ret=0
DEBUG_ENTRY_ASSERT_IRQS_OFF
+
+ .if \save_ret
+ /*
+ * If save_ret is set, the original stack contains one additional
+ * entry -- the return address. Therefore, move the address one
+ * entry below %rsp to \old_rsp.
+ */
+ leaq 8(%rsp), \old_rsp
+ .else
movq %rsp, \old_rsp
+ .endif
.if \regs
UNWIND_HINT_REGS base=\old_rsp
@@ -496,6 +506,15 @@ END(irq_entries_start)
.if \regs
UNWIND_HINT_REGS indirect=1
.endif
+
+ .if \save_ret
+ /*
+ * Push the return address to the stack. This return address can
+ * be found at the "real" original RSP, which was offset by 8 at
+ * the beginning of this macro.
+ */
+ pushq -8(\old_rsp)
+ .endif
.endm
/*
@@ -531,22 +550,7 @@ ENTRY(interrupt_entry)
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
- ret
-END(interrupt_entry)
-
-/* 0(%rsp): ~(interrupt number) */
- .macro interrupt func
- cld
-
- testb $3, CS-ORIG_RAX(%rsp)
- jz 1f
- SWAPGS
- call switch_to_thread_stack
-1:
-
- call interrupt_entry
-
- testb $3, CS(%rsp)
+ testb $3, CS+8(%rsp)
jz 1f
/*
@@ -564,10 +568,26 @@ END(interrupt_entry)
CALL_enter_from_user_mode
1:
- ENTER_IRQ_STACK old_rsp=%rdi
+ ENTER_IRQ_STACK old_rsp=%rdi save_ret=1
/* We entered an interrupt context - irqs are off: */
TRACE_IRQS_OFF
+ ret
+END(interrupt_entry)
+
+/* 0(%rsp): ~(interrupt number) */
+ .macro interrupt func
+ cld
+
+ testb $3, CS-ORIG_RAX(%rsp)
+ jz 1f
+ SWAPGS
+ call switch_to_thread_stack
+1:
+
+ call interrupt_entry
+
+ UNWIND_HINT_REGS indirect=1
call \func /* rdi points to pt_regs */
.endm
--
cgit v1.2.1
From 90a6acc4e7ebafa8672a7a1a5b23fbad3dd04130 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:10 +0100
Subject: x86/entry/64: Move the switch_to_thread_stack() call to
interrupt_entry()
We can also move the CLD, SWAPGS, and the switch_to_thread_stack() call
to the interrupt_entry() helper function. As we do not want call depths
of two, convert switch_to_thread_stack() to a macro.
However, switch_to_thread_stack() has another user in entry_64_compat.S,
which currently expects it to be a function. To keep the code changes
in this patch minimal, create a wrapper function.
The switch to a macro means that there is some binary code duplication
if CONFIG_IA32_EMULATION=y is enabled. Therefore, the size reduction
differs whether CONFIG_IA32_EMULATION is enabled or not:
CONFIG_IA32_EMULATION=y (-0.13k):
text data bss dec hex filename
17158 0 0 17158 4306 entry_64.o-orig
17028 0 0 17028 4284 entry_64.o
CONFIG_IA32_EMULATION=n (-0.27k):
text data bss dec hex filename
17158 0 0 17158 4306 entry_64.o-orig
16882 0 0 16882 41f2 entry_64.o
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-4-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 66 ++++++++++++++++++++++++++---------------------
1 file changed, 37 insertions(+), 29 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7a6ae19962ec..b45d76649eff 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -537,6 +537,31 @@ END(irq_entries_start)
decl PER_CPU_VAR(irq_count)
.endm
+/*
+ * Switch to the thread stack. This is called with the IRET frame and
+ * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
+ * space has not been allocated for them.)
+ */
+.macro DO_SWITCH_TO_THREAD_STACK
+ pushq %rdi
+ /* Need to switch before accessing the thread stack. */
+ SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
+
+ pushq 7*8(%rdi) /* regs->ss */
+ pushq 6*8(%rdi) /* regs->rsp */
+ pushq 5*8(%rdi) /* regs->eflags */
+ pushq 4*8(%rdi) /* regs->cs */
+ pushq 3*8(%rdi) /* regs->ip */
+ pushq 2*8(%rdi) /* regs->orig_ax */
+ pushq 8(%rdi) /* return address */
+ UNWIND_HINT_FUNC
+
+ movq (%rdi), %rdi
+.endm
+
/*
* Interrupt entry/exit.
*
@@ -544,8 +569,16 @@ END(irq_entries_start)
*
* Entry runs with interrupts off.
*/
+/* 8(%rsp): ~(interrupt number) */
ENTRY(interrupt_entry)
UNWIND_HINT_FUNC
+ cld
+
+ testb $3, CS-ORIG_RAX+8(%rsp)
+ jz 1f
+ SWAPGS
+ DO_SWITCH_TO_THREAD_STACK
+1:
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
@@ -577,14 +610,6 @@ END(interrupt_entry)
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
- cld
-
- testb $3, CS-ORIG_RAX(%rsp)
- jz 1f
- SWAPGS
- call switch_to_thread_stack
-1:
-
call interrupt_entry
UNWIND_HINT_REGS indirect=1
@@ -858,33 +883,16 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
-/*
- * Switch to the thread stack. This is called with the IRET frame and
- * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
- * space has not been allocated for them.)
- */
+#if defined(CONFIG_IA32_EMULATION)
+/* entry_64_compat.S::entry_INT80_compat expects this to be an ASM function */
ENTRY(switch_to_thread_stack)
UNWIND_HINT_FUNC
- pushq %rdi
- /* Need to switch before accessing the thread stack. */
- SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
- movq %rsp, %rdi
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
-
- pushq 7*8(%rdi) /* regs->ss */
- pushq 6*8(%rdi) /* regs->rsp */
- pushq 5*8(%rdi) /* regs->eflags */
- pushq 4*8(%rdi) /* regs->cs */
- pushq 3*8(%rdi) /* regs->ip */
- pushq 2*8(%rdi) /* regs->orig_ax */
- pushq 8(%rdi) /* return address */
- UNWIND_HINT_FUNC
+ DO_SWITCH_TO_THREAD_STACK
- movq (%rdi), %rdi
ret
END(switch_to_thread_stack)
+#endif
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
--
cgit v1.2.1
From 3aa99fc3e708b9cd9b4cfe2df0b7a66cf293e3cf Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:11 +0100
Subject: x86/entry/64: Remove 'interrupt' macro
It is now trivial to call interrupt_entry() and then the actual worker.
Therefore, remove the interrupt macro and open code it all.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-5-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index b45d76649eff..8ea03cf94a2d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -608,14 +608,6 @@ ENTRY(interrupt_entry)
ret
END(interrupt_entry)
-/* 0(%rsp): ~(interrupt number) */
- .macro interrupt func
- call interrupt_entry
-
- UNWIND_HINT_REGS indirect=1
- call \func /* rdi points to pt_regs */
- .endm
-
/*
* The interrupt stubs push (~vector+0x80) onto the stack and
* then jump to common_interrupt.
@@ -624,7 +616,9 @@ END(interrupt_entry)
common_interrupt:
ASM_CLAC
addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */
- interrupt do_IRQ
+ call interrupt_entry
+ UNWIND_HINT_REGS indirect=1
+ call do_IRQ /* rdi points to pt_regs */
/* 0(%rsp): old RSP */
ret_from_intr:
DISABLE_INTERRUPTS(CLBR_ANY)
@@ -820,7 +814,9 @@ ENTRY(\sym)
ASM_CLAC
pushq $~(\num)
.Lcommon_\sym:
- interrupt \do_sym
+ call interrupt_entry
+ UNWIND_HINT_REGS indirect=1
+ call \do_sym /* rdi points to pt_regs */
jmp ret_from_intr
END(\sym)
.endm
--
cgit v1.2.1
From b2855d8d2de0fa15c1ff30c69ed7756b00c48b22 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:12 +0100
Subject: x86/entry/64: Move ASM_CLAC to interrupt_entry()
Moving ASM_CLAC to interrupt_entry means two instructions (addq / pushq
and call interrupt_entry) are not covered by it. However, it offers a
noticeable size reduction (-.2k):
text data bss dec hex filename
16882 0 0 16882 41f2 entry_64.o-orig
16623 0 0 16623 40ef entry_64.o
Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-6-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8ea03cf94a2d..42a4b652469d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -572,6 +572,7 @@ END(irq_entries_start)
/* 8(%rsp): ~(interrupt number) */
ENTRY(interrupt_entry)
UNWIND_HINT_FUNC
+ ASM_CLAC
cld
testb $3, CS-ORIG_RAX+8(%rsp)
@@ -614,7 +615,6 @@ END(interrupt_entry)
*/
.p2align CONFIG_X86_L1_CACHE_SHIFT
common_interrupt:
- ASM_CLAC
addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */
call interrupt_entry
UNWIND_HINT_REGS indirect=1
@@ -811,7 +811,6 @@ END(common_interrupt)
.macro apicinterrupt3 num sym do_sym
ENTRY(\sym)
UNWIND_HINT_IRET_REGS
- ASM_CLAC
pushq $~(\num)
.Lcommon_\sym:
call interrupt_entry
--
cgit v1.2.1
From f3d415ea46968ae1f9cbb9e201601d7207ce74c7 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 20 Feb 2018 22:01:13 +0100
Subject: x86/entry/64: Open-code switch_to_thread_stack()
Open-code the two instances which called switch_to_thread_stack(). This
allows us to remove the wrapper around DO_SWITCH_TO_THREAD_STACK.
While at it, update the UNWIND hint to reflect where the IRET frame is,
and update the commentary to reflect what we are actually doing here.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180220210113.6725-7-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64.S | 76 +++++++++++++++++++++-------------------
arch/x86/entry/entry_64_compat.S | 17 +++++++--
2 files changed, 55 insertions(+), 38 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 42a4b652469d..d5c7f18f79ac 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -538,17 +538,48 @@ END(irq_entries_start)
.endm
/*
- * Switch to the thread stack. This is called with the IRET frame and
- * orig_ax on the stack. (That is, RDI..R12 are not on the stack and
- * space has not been allocated for them.)
+ * Interrupt entry helper function.
+ *
+ * Entry runs with interrupts off. Stack layout at entry:
+ * +----------------------------------------------------+
+ * | regs->ss |
+ * | regs->rsp |
+ * | regs->eflags |
+ * | regs->cs |
+ * | regs->ip |
+ * +----------------------------------------------------+
+ * | regs->orig_ax = ~(interrupt number) |
+ * +----------------------------------------------------+
+ * | return address |
+ * +----------------------------------------------------+
*/
-.macro DO_SWITCH_TO_THREAD_STACK
+ENTRY(interrupt_entry)
+ UNWIND_HINT_FUNC
+ ASM_CLAC
+ cld
+
+ testb $3, CS-ORIG_RAX+8(%rsp)
+ jz 1f
+ SWAPGS
+
+ /*
+ * Switch to the thread stack. The IRET frame and orig_ax are
+ * on the stack, as well as the return address. RDI..R12 are
+ * not (yet) on the stack and space has not (yet) been
+ * allocated for them.
+ */
pushq %rdi
+
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
+
+ /*
+ * We have RDI, return address, and orig_ax on the stack on
+ * top of the IRET frame. That means offset=24
+ */
+ UNWIND_HINT_IRET_REGS base=%rdi offset=24
pushq 7*8(%rdi) /* regs->ss */
pushq 6*8(%rdi) /* regs->rsp */
@@ -560,25 +591,6 @@ END(irq_entries_start)
UNWIND_HINT_FUNC
movq (%rdi), %rdi
-.endm
-
-/*
- * Interrupt entry/exit.
- *
- * Interrupt entry points save only callee clobbered registers in fast path.
- *
- * Entry runs with interrupts off.
- */
-/* 8(%rsp): ~(interrupt number) */
-ENTRY(interrupt_entry)
- UNWIND_HINT_FUNC
- ASM_CLAC
- cld
-
- testb $3, CS-ORIG_RAX+8(%rsp)
- jz 1f
- SWAPGS
- DO_SWITCH_TO_THREAD_STACK
1:
PUSH_AND_CLEAR_REGS save_ret=1
@@ -592,7 +604,7 @@ ENTRY(interrupt_entry)
*
* We need to tell lockdep that IRQs are off. We can't do this until
* we fix gsbase, and we should do it before enter_from_user_mode
- * (which can take locks). Since TRACE_IRQS_OFF idempotent,
+ * (which can take locks). Since TRACE_IRQS_OFF is idempotent,
* the simplest way to handle it is to just call it twice if
* we enter from user mode. There's no reason to optimize this since
* TRACE_IRQS_OFF is a no-op if lockdep is off.
@@ -609,6 +621,9 @@ ENTRY(interrupt_entry)
ret
END(interrupt_entry)
+
+/* Interrupt entry/exit. */
+
/*
* The interrupt stubs push (~vector+0x80) onto the stack and
* then jump to common_interrupt.
@@ -878,17 +893,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
-#if defined(CONFIG_IA32_EMULATION)
-/* entry_64_compat.S::entry_INT80_compat expects this to be an ASM function */
-ENTRY(switch_to_thread_stack)
- UNWIND_HINT_FUNC
-
- DO_SWITCH_TO_THREAD_STACK
-
- ret
-END(switch_to_thread_stack)
-#endif
-
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
UNWIND_HINT_IRET_REGS offset=\has_error_code*8
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 364ea4a207be..e811dd9c5e99 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -347,10 +347,23 @@ ENTRY(entry_INT80_compat)
*/
movl %eax, %eax
+ /* switch to thread stack expects orig_ax and rdi to be pushed */
pushq %rax /* pt_regs->orig_ax */
+ pushq %rdi /* pt_regs->di */
+
+ /* Need to switch before accessing the thread stack. */
+ SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
+ movq %rsp, %rdi
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+
+ pushq 6*8(%rdi) /* regs->ss */
+ pushq 5*8(%rdi) /* regs->rsp */
+ pushq 4*8(%rdi) /* regs->eflags */
+ pushq 3*8(%rdi) /* regs->cs */
+ pushq 2*8(%rdi) /* regs->ip */
+ pushq 1*8(%rdi) /* regs->orig_ax */
- /* switch to thread stack expects orig_ax to be pushed */
- call switch_to_thread_stack
+ movq (%rdi), %rdi /* restore %rdi */
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
--
cgit v1.2.1
From 0ca7d5baa1787e5f2a7abd6bfca3303b1bbb48ac Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Tue, 20 Feb 2018 20:42:14 -0600
Subject: x86/entry/64: Simplify ENCODE_FRAME_POINTER
On 64-bit, the stack pointer is always aligned on interrupt, so instead
of setting the LSB of the pt_regs address, we can just add 1 to it.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180221024214.lhl5jfgw33c4vz3m@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/calling.h | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 5d10b7a85cad..be63330c5511 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -181,12 +181,7 @@ For 32-bit we have the following conventions - kernel is built with
*/
.macro ENCODE_FRAME_POINTER ptregs_offset=0
#ifdef CONFIG_FRAME_POINTER
- .if \ptregs_offset
- leaq \ptregs_offset(%rsp), %rbp
- .else
- mov %rsp, %rbp
- .endif
- orq $0x1, %rbp
+ leaq 1+\ptregs_offset(%rsp), %rbp
#endif
.endm
--
cgit v1.2.1
From a368d7fd2a3c6babb852fe974018dd97916bcd3b Mon Sep 17 00:00:00 2001
From: Jan Beulich <JBeulich@suse.com>
Date: Mon, 26 Feb 2018 04:11:21 -0700
Subject: x86/entry/64: Add instruction suffix
Omitting suffixes from instructions in AT&T mode is bad practice when
operand size cannot be determined by the assembler from register
operands, and is likely going to be warned about by upstream gas in the
future (mine does already). Add the single missing suffix here.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/5A93F96902000078001ABAC8@prv-mh.provo.novell.com
---
arch/x86/entry/entry_64.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index d5c7f18f79ac..805f52703ee3 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -55,7 +55,7 @@ END(native_usergs_sysret64)
.macro TRACE_IRQS_FLAGS flags:req
#ifdef CONFIG_TRACE_IRQFLAGS
- bt $9, \flags /* interrupts off? */
+ btl $9, \flags /* interrupts off? */
jnc 1f
TRACE_IRQS_ON
1:
--
cgit v1.2.1
From b411991e0ca880d8e7f5eb117c05de6f4b47a2c7 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 6 Mar 2018 22:18:03 +0100
Subject: x86/syscalls/32: Simplify $entry == $compat entries
If the compat entry point is equivalent to the native entry point, it
does not need to be specified explicitly.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@amacapital.net
Cc: viro@zeniv.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/syscalls/syscall_32.tbl | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 448ac2161112..ad5e95a369e4 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -8,7 +8,7 @@
#
0 i386 restart_syscall sys_restart_syscall
1 i386 exit sys_exit
-2 i386 fork sys_fork sys_fork
+2 i386 fork sys_fork
3 i386 read sys_read
4 i386 write sys_write
5 i386 open sys_open compat_sys_open
@@ -78,7 +78,7 @@
69 i386 ssetmask sys_ssetmask
70 i386 setreuid sys_setreuid16
71 i386 setregid sys_setregid16
-72 i386 sigsuspend sys_sigsuspend sys_sigsuspend
+72 i386 sigsuspend sys_sigsuspend
73 i386 sigpending sys_sigpending compat_sys_sigpending
74 i386 sethostname sys_sethostname
75 i386 setrlimit sys_setrlimit compat_sys_setrlimit
@@ -196,7 +196,7 @@
187 i386 sendfile sys_sendfile compat_sys_sendfile
188 i386 getpmsg
189 i386 putpmsg
-190 i386 vfork sys_vfork sys_vfork
+190 i386 vfork sys_vfork
191 i386 ugetrlimit sys_getrlimit compat_sys_getrlimit
192 i386 mmap2 sys_mmap_pgoff
193 i386 truncate64 sys_truncate64 sys32_truncate64
--
cgit v1.2.1
From 4ddb45db30851b2269101ee8969f079b028dd257 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 6 Mar 2018 22:18:07 +0100
Subject: x86/syscalls: Use COMPAT_SYSCALL_DEFINEx() macros for x86-only compat
syscalls
While at it, convert declarations of type "unsigned" to "unsigned int".
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@amacapital.net
Cc: viro@zeniv.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/syscalls/syscall_32.tbl | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ad5e95a369e4..e7fd0a76bf99 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -13,7 +13,7 @@
4 i386 write sys_write
5 i386 open sys_open compat_sys_open
6 i386 close sys_close
-7 i386 waitpid sys_waitpid sys32_waitpid
+7 i386 waitpid sys_waitpid compat_sys_x86_waitpid
8 i386 creat sys_creat
9 i386 link sys_link
10 i386 unlink sys_unlink
@@ -96,7 +96,7 @@
87 i386 swapon sys_swapon
88 i386 reboot sys_reboot
89 i386 readdir sys_old_readdir compat_sys_old_readdir
-90 i386 mmap sys_old_mmap sys32_mmap
+90 i386 mmap sys_old_mmap compat_sys_x86_mmap
91 i386 munmap sys_munmap
92 i386 truncate sys_truncate compat_sys_truncate
93 i386 ftruncate sys_ftruncate compat_sys_ftruncate
@@ -186,8 +186,8 @@
177 i386 rt_sigtimedwait sys_rt_sigtimedwait compat_sys_rt_sigtimedwait
178 i386 rt_sigqueueinfo sys_rt_sigqueueinfo compat_sys_rt_sigqueueinfo
179 i386 rt_sigsuspend sys_rt_sigsuspend
-180 i386 pread64 sys_pread64 sys32_pread
-181 i386 pwrite64 sys_pwrite64 sys32_pwrite
+180 i386 pread64 sys_pread64 compat_sys_x86_pread
+181 i386 pwrite64 sys_pwrite64 compat_sys_x86_pwrite
182 i386 chown sys_chown16
183 i386 getcwd sys_getcwd
184 i386 capget sys_capget
@@ -199,11 +199,11 @@
190 i386 vfork sys_vfork
191 i386 ugetrlimit sys_getrlimit compat_sys_getrlimit
192 i386 mmap2 sys_mmap_pgoff
-193 i386 truncate64 sys_truncate64 sys32_truncate64
-194 i386 ftruncate64 sys_ftruncate64 sys32_ftruncate64
-195 i386 stat64 sys_stat64 sys32_stat64
-196 i386 lstat64 sys_lstat64 sys32_lstat64
-197 i386 fstat64 sys_fstat64 sys32_fstat64
+193 i386 truncate64 sys_truncate64 compat_sys_x86_truncate64
+194 i386 ftruncate64 sys_ftruncate64 compat_sys_x86_ftruncate64
+195 i386 stat64 sys_stat64 compat_sys_x86_stat64
+196 i386 lstat64 sys_lstat64 compat_sys_x86_lstat64
+197 i386 fstat64 sys_fstat64 compat_sys_x86_fstat64
198 i386 lchown32 sys_lchown
199 i386 getuid32 sys_getuid
200 i386 getgid32 sys_getgid
@@ -231,7 +231,7 @@
# 222 is unused
# 223 is unused
224 i386 gettid sys_gettid
-225 i386 readahead sys_readahead sys32_readahead
+225 i386 readahead sys_readahead compat_sys_x86_readahead
226 i386 setxattr sys_setxattr
227 i386 lsetxattr sys_lsetxattr
228 i386 fsetxattr sys_fsetxattr
@@ -256,7 +256,7 @@
247 i386 io_getevents sys_io_getevents compat_sys_io_getevents
248 i386 io_submit sys_io_submit compat_sys_io_submit
249 i386 io_cancel sys_io_cancel
-250 i386 fadvise64 sys_fadvise64 sys32_fadvise64
+250 i386 fadvise64 sys_fadvise64 compat_sys_x86_fadvise64
# 251 is available for reuse (was briefly sys_set_zone_reclaim)
252 i386 exit_group sys_exit_group
253 i386 lookup_dcookie sys_lookup_dcookie compat_sys_lookup_dcookie
@@ -278,7 +278,7 @@
269 i386 fstatfs64 sys_fstatfs64 compat_sys_fstatfs64
270 i386 tgkill sys_tgkill
271 i386 utimes sys_utimes compat_sys_utimes
-272 i386 fadvise64_64 sys_fadvise64_64 sys32_fadvise64_64
+272 i386 fadvise64_64 sys_fadvise64_64 compat_sys_x86_fadvise64_64
273 i386 vserver
274 i386 mbind sys_mbind
275 i386 get_mempolicy sys_get_mempolicy compat_sys_get_mempolicy
@@ -306,7 +306,7 @@
297 i386 mknodat sys_mknodat
298 i386 fchownat sys_fchownat
299 i386 futimesat sys_futimesat compat_sys_futimesat
-300 i386 fstatat64 sys_fstatat64 sys32_fstatat
+300 i386 fstatat64 sys_fstatat64 compat_sys_x86_fstatat
301 i386 unlinkat sys_unlinkat
302 i386 renameat sys_renameat
303 i386 linkat sys_linkat
@@ -320,7 +320,7 @@
311 i386 set_robust_list sys_set_robust_list compat_sys_set_robust_list
312 i386 get_robust_list sys_get_robust_list compat_sys_get_robust_list
313 i386 splice sys_splice
-314 i386 sync_file_range sys_sync_file_range sys32_sync_file_range
+314 i386 sync_file_range sys_sync_file_range compat_sys_x86_sync_file_range
315 i386 tee sys_tee
316 i386 vmsplice sys_vmsplice compat_sys_vmsplice
317 i386 move_pages sys_move_pages compat_sys_move_pages
@@ -330,7 +330,7 @@
321 i386 signalfd sys_signalfd compat_sys_signalfd
322 i386 timerfd_create sys_timerfd_create
323 i386 eventfd sys_eventfd
-324 i386 fallocate sys_fallocate sys32_fallocate
+324 i386 fallocate sys_fallocate compat_sys_x86_fallocate
325 i386 timerfd_settime sys_timerfd_settime compat_sys_timerfd_settime
326 i386 timerfd_gettime sys_timerfd_gettime compat_sys_timerfd_gettime
327 i386 signalfd4 sys_signalfd4 compat_sys_signalfd4
--
cgit v1.2.1
From af52201d991624d2d5adce2c123805b3d42a8d4d Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 6 Mar 2018 22:18:08 +0100
Subject: x86/entry: Do not special-case clone(2) in compat entry
With the CPU renaming registers on its own, and all the overhead of the
syscall entry/exit, it is doubtful whether the compiled output of
mov %r8, %rax
mov %rcx, %r8
mov %rax, %rcx
jmpq sys_clone
is measurably slower than the hand-crafted version of
xchg %r8, %rcx
So get rid of this special case.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@amacapital.net
Cc: viro@zeniv.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64_compat.S | 12 ------------
arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
2 files changed, 1 insertion(+), 13 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index e811dd9c5e99..ff61b7bb750b 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -406,15 +406,3 @@ ENTRY(entry_INT80_compat)
TRACE_IRQS_ON
jmp swapgs_restore_regs_and_return_to_usermode
END(entry_INT80_compat)
-
-ENTRY(stub32_clone)
- /*
- * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr).
- * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val).
- *
- * The native 64-bit kernel's sys_clone() implements the latter,
- * so we need to swap arguments here before calling it:
- */
- xchg %r8, %rcx
- jmp sys_clone
-ENDPROC(stub32_clone)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index e7fd0a76bf99..2a5e99cff859 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -126,7 +126,7 @@
117 i386 ipc sys_ipc compat_sys_ipc
118 i386 fsync sys_fsync
119 i386 sigreturn sys_sigreturn sys32_sigreturn
-120 i386 clone sys_clone stub32_clone
+120 i386 clone sys_clone compat_sys_x86_clone
121 i386 setdomainname sys_setdomainname
122 i386 uname sys_newuname
123 i386 modify_ldt sys_modify_ldt
--
cgit v1.2.1
From 91c5f0de64a226e0d9c558b26ef7c2655ef31cca Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 6 Mar 2018 22:18:09 +0100
Subject: x86/entry/64/compat: Save one instruction in entry_INT80_compat()
As %rdi is never user except in the following push, there is no
need to restore %rdi to the original value.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: luto@amacapital.net
Cc: viro@zeniv.linux.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/entry_64_compat.S | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index ff61b7bb750b..08425c42f8b7 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -363,9 +363,7 @@ ENTRY(entry_INT80_compat)
pushq 2*8(%rdi) /* regs->ip */
pushq 1*8(%rdi) /* regs->orig_ax */
- movq (%rdi), %rdi /* restore %rdi */
-
- pushq %rdi /* pt_regs->di */
+ pushq (%rdi) /* pt_regs->di */
pushq %rsi /* pt_regs->si */
pushq %rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
--
cgit v1.2.1
From 076ca272a14cea558b1092ec85cea08510283f2a Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@kernel.org>
Date: Wed, 7 Mar 2018 11:12:27 -0800
Subject: x86/vsyscall/64: Drop "native" vsyscalls
Since Linux v3.2, vsyscalls have been deprecated and slow. From v3.2
on, Linux had three vsyscall modes: "native", "emulate", and "none".
"emulate" is the default. All known user programs work correctly in
emulate mode, but vsyscalls turn into page faults and are emulated.
This is very slow. In "native" mode, the vsyscall page is easily
usable as an exploit gadget, but vsyscalls are a bit faster -- they
turn into normal syscalls. (This is in contrast to vDSO functions,
which can be much faster than syscalls.) In "none" mode, there are
no vsyscalls.
For all practical purposes, "native" was really just a chicken bit
in case something went wrong with the emulation. It's been over six
years, and nothing has gone wrong. Delete it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/519fee5268faea09ae550776ce969fa6e88668b0.1520449896.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/entry/vsyscall/vsyscall_64.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
(limited to 'arch/x86/entry')
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 577fa8adb785..8560ef68a9d6 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -42,10 +42,8 @@
#define CREATE_TRACE_POINTS
#include "vsyscall_trace.h"
-static enum { EMULATE, NATIVE, NONE } vsyscall_mode =
-#if defined(CONFIG_LEGACY_VSYSCALL_NATIVE)
- NATIVE;
-#elif defined(CONFIG_LEGACY_VSYSCALL_NONE)
+static enum { EMULATE, NONE } vsyscall_mode =
+#ifdef CONFIG_LEGACY_VSYSCALL_NONE
NONE;
#else
EMULATE;
@@ -56,8 +54,6 @@ static int __init vsyscall_setup(char *str)
if (str) {
if (!strcmp("emulate", str))
vsyscall_mode = EMULATE;
- else if (!strcmp("native", str))
- vsyscall_mode = NATIVE;
else if (!strcmp("none", str))
vsyscall_mode = NONE;
else
@@ -139,10 +135,6 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
WARN_ON_ONCE(address != regs->ip);
- /* This should be unreachable in NATIVE mode. */
- if (WARN_ON(vsyscall_mode == NATIVE))
- return false;
-
if (vsyscall_mode == NONE) {
warn_bad_vsyscall(KERN_INFO, regs,
"vsyscall attempted with vsyscall=none");
@@ -370,9 +362,7 @@ void __init map_vsyscall(void)
if (vsyscall_mode != NONE) {
__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
- vsyscall_mode == NATIVE
- ? PAGE_KERNEL_VSYSCALL
- : PAGE_KERNEL_VVAR);
+ PAGE_KERNEL_VVAR);
set_vsyscall_pgtable_user_bits(swapper_pg_dir);
}
--
cgit v1.2.1