* [PATCH 1/7] x86/entry: Anchor annotation
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-26 15:04 ` Josh Poimboeuf
2022-05-26 10:52 ` [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules Peter Zijlstra
` (5 subsequent siblings)
6 siblings, 1 reply; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland
x86_64-allmodconfig gives:
vmlinux.o: warning: objtool: entry_SYSCALL_compat+0x0: ANNOTATE_NOENDBR on ENDBR
This is due to:
ANNOTATE_NOENDBR
SYM_CODE_END(entry_SYSENTER_compat)
SYM_CODE_START(entry_SYSCALL_compat)
UNWIND_HINT_EMPTY
ENDBR
And the hint then landing on the first instruction of the next symbol,
which happens to be ENDBR. Stick in an int3 to anchor the annotation
in the previous symbol.
Fixes: 3e3f06950434 ("x86/ibt: Annotate text references")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/entry/entry_64_compat.S | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -124,6 +124,7 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_af
jmp .Lsysenter_flags_fixed
SYM_INNER_LABEL(__end_entry_SYSENTER_compat, SYM_L_GLOBAL)
ANNOTATE_NOENDBR // is_sysenter_singlestep
+ int3
SYM_CODE_END(entry_SYSENTER_compat)
/*
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 1/7] x86/entry: Anchor annotation
2022-05-26 10:52 ` [PATCH 1/7] x86/entry: Anchor annotation Peter Zijlstra
@ 2022-05-26 15:04 ` Josh Poimboeuf
0 siblings, 0 replies; 21+ messages in thread
From: Josh Poimboeuf @ 2022-05-26 15:04 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, elver, jbaron, rostedt, ardb, mark.rutland
On Thu, May 26, 2022 at 12:52:53PM +0200, Peter Zijlstra wrote:
> x86_64-allmodconfig gives:
>
> vmlinux.o: warning: objtool: entry_SYSCALL_compat+0x0: ANNOTATE_NOENDBR on ENDBR
>
> This is due to:
>
> ANNOTATE_NOENDBR
> SYM_CODE_END(entry_SYSENTER_compat)
> SYM_CODE_START(entry_SYSCALL_compat)
> UNWIND_HINT_EMPTY
> ENDBR
>
> And the hint then landing on the first instruction of the next symbol,
> which happens to be ENDBR. Stick in an int3 to anchor the annotation
> in the previous symbol.
>
> Fixes: 3e3f06950434 ("x86/ibt: Annotate text references")
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/x86/entry/entry_64_compat.S | 1 +
> 1 file changed, 1 insertion(+)
>
> --- a/arch/x86/entry/entry_64_compat.S
> +++ b/arch/x86/entry/entry_64_compat.S
> @@ -124,6 +124,7 @@ SYM_INNER_LABEL(entry_SYSENTER_compat_af
> jmp .Lsysenter_flags_fixed
> SYM_INNER_LABEL(__end_entry_SYSENTER_compat, SYM_L_GLOBAL)
> ANNOTATE_NOENDBR // is_sysenter_singlestep
> + int3
> SYM_CODE_END(entry_SYSENTER_compat)
Hm, I get the feeling this warning is pretty much useless anyway. Can
we just get rid of the warning instead?
--
Josh
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
2022-05-26 10:52 ` [PATCH 1/7] x86/entry: Anchor annotation Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-26 15:05 ` Josh Poimboeuf
2022-05-26 10:52 ` [PATCH 3/7] objtool: Mark __ubsan_handle_builtin_unreachable() as noreturn Peter Zijlstra
` (4 subsequent siblings)
6 siblings, 1 reply; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland
Extend the UNWIND hint driven rules for ENDBR placement. Currently
objtool expects an ENDBR at any UNWINT_HINT_IRET_REGS that is at +0 of
an STB_GLOBAL symbol, with the expectation that this is an exception
entry point.
Extend this to also expect ENDBR at UNWIND_HINT_EMPTY at +0 for
STB_GLOBAL symbols, with the expectation that these are also machine
entry points (SYSCALL et. al.).
This guarantees all machine entry points are covered by objtool rules at
the expense of a few additional false positives:
vmlinux.o: warning: objtool: startup_64+0x0: UNWIND_HINT_EMPTY without ENDBR
vmlinux.o: warning: objtool: start_cpu0+0x0: UNWIND_HINT_EMPTY without ENDBR
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/head_64.S | 2 ++
tools/objtool/check.c | 23 ++++++++++++++++++-----
2 files changed, 20 insertions(+), 5 deletions(-)
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -43,6 +43,7 @@ L3_START_KERNEL = pud_index(__START_KERN
.code64
SYM_CODE_START_NOALIGN(startup_64)
UNWIND_HINT_EMPTY
+ ANNOTATE_NOENDBR
/*
* At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
* and someone has loaded an identity mapped page table
@@ -371,6 +372,7 @@ SYM_CODE_END(secondary_startup_64)
*/
SYM_CODE_START(start_cpu0)
UNWIND_HINT_EMPTY
+ ANNOTATE_NOENDBR
movq initial_stack(%rip), %rsp
jmp .Ljump_to_C_code
SYM_CODE_END(start_cpu0)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1947,14 +1947,27 @@ static int read_unwind_hints(struct objt
insn->hint = true;
- if (opts.ibt && hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+ if (opts.ibt) {
struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
- if (sym && sym->bind == STB_GLOBAL &&
- insn->type != INSN_ENDBR && !insn->noendbr) {
- WARN_FUNC("UNWIND_HINT_IRET_REGS without ENDBR",
- insn->sec, insn->offset);
+ if (!sym || sym->bind != STB_GLOBAL)
+ goto no_entry;
+
+ if (hint->type == UNWIND_HINT_TYPE_CALL && !hint->sp_reg) {
+ if (insn->type != INSN_ENDBR && !insn->noendbr) {
+ WARN_FUNC("UNWIND_HINT_EMPTY without ENDBR",
+ insn->sec, insn->offset);
+ }
+ }
+
+ if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+ if (insn->type != INSN_ENDBR && !insn->noendbr) {
+ WARN_FUNC("UNWIND_HINT_IRET_REGS without ENDBR",
+ insn->sec, insn->offset);
+ }
}
+
+no_entry: ;
}
if (hint->type == UNWIND_HINT_TYPE_FUNC) {
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules
2022-05-26 10:52 ` [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules Peter Zijlstra
@ 2022-05-26 15:05 ` Josh Poimboeuf
2022-05-28 14:09 ` Peter Zijlstra
0 siblings, 1 reply; 21+ messages in thread
From: Josh Poimboeuf @ 2022-05-26 15:05 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, elver, jbaron, rostedt, ardb, mark.rutland
On Thu, May 26, 2022 at 12:52:54PM +0200, Peter Zijlstra wrote:
> Extend the UNWIND hint driven rules for ENDBR placement. Currently
> objtool expects an ENDBR at any UNWINT_HINT_IRET_REGS that is at +0 of
> an STB_GLOBAL symbol, with the expectation that this is an exception
> entry point.
>
> Extend this to also expect ENDBR at UNWIND_HINT_EMPTY at +0 for
> STB_GLOBAL symbols, with the expectation that these are also machine
> entry points (SYSCALL et. al.).
>
> This guarantees all machine entry points are covered by objtool rules at
> the expense of a few additional false positives:
>
> vmlinux.o: warning: objtool: startup_64+0x0: UNWIND_HINT_EMPTY without ENDBR
> vmlinux.o: warning: objtool: start_cpu0+0x0: UNWIND_HINT_EMPTY without ENDBR
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
I can't remember if this was my bright idea, but it feels kind of
arbitrary. Hopefully there won't be a lot of false positives.
Anyway, won't SYSCALL-type symbols typically be referenced elsewhere in
the kernel and thus be found by the regular IBT validation?
Do you have any examples of where this warning would trigger if there
were a missing ENDBR?
--
Josh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules
2022-05-26 15:05 ` Josh Poimboeuf
@ 2022-05-28 14:09 ` Peter Zijlstra
0 siblings, 0 replies; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-28 14:09 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: x86, jpoimboe, linux-kernel, elver, jbaron, rostedt, ardb, mark.rutland
On Thu, May 26, 2022 at 08:05:49AM -0700, Josh Poimboeuf wrote:
> On Thu, May 26, 2022 at 12:52:54PM +0200, Peter Zijlstra wrote:
> > Extend the UNWIND hint driven rules for ENDBR placement. Currently
> > objtool expects an ENDBR at any UNWINT_HINT_IRET_REGS that is at +0 of
> > an STB_GLOBAL symbol, with the expectation that this is an exception
> > entry point.
> >
> > Extend this to also expect ENDBR at UNWIND_HINT_EMPTY at +0 for
> > STB_GLOBAL symbols, with the expectation that these are also machine
> > entry points (SYSCALL et. al.).
> >
> > This guarantees all machine entry points are covered by objtool rules at
> > the expense of a few additional false positives:
> >
> > vmlinux.o: warning: objtool: startup_64+0x0: UNWIND_HINT_EMPTY without ENDBR
> > vmlinux.o: warning: objtool: start_cpu0+0x0: UNWIND_HINT_EMPTY without ENDBR
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
> I can't remember if this was my bright idea, but it feels kind of
> arbitrary. Hopefully there won't be a lot of false positives.
The existing UNWIND_HINT_IRET_REGS at +0 was your idea, I'm just trying
to cover more.
> Anyway, won't SYSCALL-type symbols typically be referenced elsewhere in
> the kernel and thus be found by the regular IBT validation?
They do indeed, and that's what we've been relying on. I just figured it
would be more consistent to have rules covering all machine entry
points.
(also all the Xen entry points are EMPTY like).
> Do you have any examples of where this warning would trigger if there
> were a missing ENDBR?
No.
Anyway, I can drop these first two patches for now.
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 3/7] objtool: Mark __ubsan_handle_builtin_unreachable() as noreturn
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
2022-05-26 10:52 ` [PATCH 1/7] x86/entry: Anchor annotation Peter Zijlstra
2022-05-26 10:52 ` [PATCH 2/7] objtool: Extend UNWIND_HINT based ENDBR rules Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-30 13:17 ` Marco Elver
2022-05-26 10:52 ` [PATCH 4/7] x86/cpu: Elide KCSAN for cpu_has() and friends Peter Zijlstra
` (3 subsequent siblings)
6 siblings, 1 reply; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
fs/ntfs3/ntfs3.prelink.o: warning: objtool: ni_read_frame() falls through to next function ni_readpage_cmpr.cold()
That is in fact:
000000000000124a <ni_read_frame.cold>:
124a: 44 89 e0 mov %r12d,%eax
124d: 0f b6 55 98 movzbl -0x68(%rbp),%edx
1251: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 1254: R_X86_64_32S .data+0x1380
1258: 48 89 c6 mov %rax,%rsi
125b: e8 00 00 00 00 call 1260 <ni_read_frame.cold+0x16> 125c: R_X86_64_PLT32 __ubsan_handle_shift_out_of_bounds-0x4
1260: 48 8d 7d cc lea -0x34(%rbp),%rdi
1264: e8 00 00 00 00 call 1269 <ni_read_frame.cold+0x1f> 1265: R_X86_64_PLT32 __tsan_read4-0x4
1269: 8b 45 cc mov -0x34(%rbp),%eax
126c: e9 00 00 00 00 jmp 1271 <ni_read_frame.cold+0x27> 126d: R_X86_64_PC32 .text+0x19109
1271: 48 8b 75 a0 mov -0x60(%rbp),%rsi
1275: 48 63 d0 movslq %eax,%rdx
1278: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 127b: R_X86_64_32S .data+0x13a0
127f: 89 45 88 mov %eax,-0x78(%rbp)
1282: e8 00 00 00 00 call 1287 <ni_read_frame.cold+0x3d> 1283: R_X86_64_PLT32 __ubsan_handle_shift_out_of_bounds-0x4
1287: 8b 45 88 mov -0x78(%rbp),%eax
128a: e9 00 00 00 00 jmp 128f <ni_read_frame.cold+0x45> 128b: R_X86_64_PC32 .text+0x19098
128f: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 1292: R_X86_64_32S .data+0x11f0
1296: e8 00 00 00 00 call 129b <ni_readpage_cmpr.cold> 1297: R_X86_64_PLT32 __ubsan_handle_builtin_unreachable-0x4
000000000000129b <ni_readpage_cmpr.cold>:
Tell objtool that __ubsan_handle_builtin_unreachable() is a noreturn.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220502091514.GB479834@worktop.programming.kicks-ass.net
---
tools/objtool/check.c | 1 +
1 file changed, 1 insertion(+)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -185,6 +185,7 @@ static bool __dead_end_function(struct o
"stop_this_cpu",
"__invalid_creds",
"cpu_startup_entry",
+ "__ubsan_handle_builtin_unreachable",
};
if (!func)
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 3/7] objtool: Mark __ubsan_handle_builtin_unreachable() as noreturn
2022-05-26 10:52 ` [PATCH 3/7] objtool: Mark __ubsan_handle_builtin_unreachable() as noreturn Peter Zijlstra
@ 2022-05-30 13:17 ` Marco Elver
0 siblings, 0 replies; 21+ messages in thread
From: Marco Elver @ 2022-05-30 13:17 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
On Thu, May 26, 2022 at 12:52PM +0200, Peter Zijlstra wrote:
> fs/ntfs3/ntfs3.prelink.o: warning: objtool: ni_read_frame() falls through to next function ni_readpage_cmpr.cold()
>
> That is in fact:
>
> 000000000000124a <ni_read_frame.cold>:
> 124a: 44 89 e0 mov %r12d,%eax
> 124d: 0f b6 55 98 movzbl -0x68(%rbp),%edx
> 1251: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 1254: R_X86_64_32S .data+0x1380
> 1258: 48 89 c6 mov %rax,%rsi
> 125b: e8 00 00 00 00 call 1260 <ni_read_frame.cold+0x16> 125c: R_X86_64_PLT32 __ubsan_handle_shift_out_of_bounds-0x4
> 1260: 48 8d 7d cc lea -0x34(%rbp),%rdi
> 1264: e8 00 00 00 00 call 1269 <ni_read_frame.cold+0x1f> 1265: R_X86_64_PLT32 __tsan_read4-0x4
> 1269: 8b 45 cc mov -0x34(%rbp),%eax
> 126c: e9 00 00 00 00 jmp 1271 <ni_read_frame.cold+0x27> 126d: R_X86_64_PC32 .text+0x19109
> 1271: 48 8b 75 a0 mov -0x60(%rbp),%rsi
> 1275: 48 63 d0 movslq %eax,%rdx
> 1278: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 127b: R_X86_64_32S .data+0x13a0
> 127f: 89 45 88 mov %eax,-0x78(%rbp)
> 1282: e8 00 00 00 00 call 1287 <ni_read_frame.cold+0x3d> 1283: R_X86_64_PLT32 __ubsan_handle_shift_out_of_bounds-0x4
> 1287: 8b 45 88 mov -0x78(%rbp),%eax
> 128a: e9 00 00 00 00 jmp 128f <ni_read_frame.cold+0x45> 128b: R_X86_64_PC32 .text+0x19098
> 128f: 48 c7 c7 00 00 00 00 mov $0x0,%rdi 1292: R_X86_64_32S .data+0x11f0
> 1296: e8 00 00 00 00 call 129b <ni_readpage_cmpr.cold> 1297: R_X86_64_PLT32 __ubsan_handle_builtin_unreachable-0x4
>
> 000000000000129b <ni_readpage_cmpr.cold>:
>
> Tell objtool that __ubsan_handle_builtin_unreachable() is a noreturn.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://lkml.kernel.org/r/20220502091514.GB479834@worktop.programming.kicks-ass.net
Acked-by: Marco Elver <elver@google.com>
> ---
> tools/objtool/check.c | 1 +
> 1 file changed, 1 insertion(+)
>
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -185,6 +185,7 @@ static bool __dead_end_function(struct o
> "stop_this_cpu",
> "__invalid_creds",
> "cpu_startup_entry",
> + "__ubsan_handle_builtin_unreachable",
> };
>
> if (!func)
>
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 4/7] x86/cpu: Elide KCSAN for cpu_has() and friends
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
` (2 preceding siblings ...)
2022-05-26 10:52 ` [PATCH 3/7] objtool: Mark __ubsan_handle_builtin_unreachable() as noreturn Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-30 13:14 ` Marco Elver
2022-05-26 10:52 ` [PATCH 5/7] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds Peter Zijlstra
` (2 subsequent siblings)
6 siblings, 1 reply; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
As x86 uses the <asm-generic/bitops/instrumented-*.h> headers, the
regular forms of all bitops are instrumented with explicit calls to
KASAN and KCSAN checks. As these are explicit calls, these are not
suppressed by the noinstr function attribute.
This can result in calls to those check functions in noinstr code, which
objtool warns about:
vmlinux.o: warning: objtool: enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x28: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x24: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
Prevent this by using the arch_*() bitops, which are the underlying
bitops without explciit instrumentation.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220502111216.290518605@infradead.org
---
arch/x86/include/asm/cpufeature.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -51,7 +51,7 @@ extern const char * const x86_power_flag
extern const char * const x86_bug_flags[NBUGINTS*32];
#define test_cpu_cap(c, bit) \
- test_bit(bit, (unsigned long *)((c)->x86_capability))
+ arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
/*
* There are 32 bits/features in each mask word. The high bits
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 4/7] x86/cpu: Elide KCSAN for cpu_has() and friends
2022-05-26 10:52 ` [PATCH 4/7] x86/cpu: Elide KCSAN for cpu_has() and friends Peter Zijlstra
@ 2022-05-30 13:14 ` Marco Elver
0 siblings, 0 replies; 21+ messages in thread
From: Marco Elver @ 2022-05-30 13:14 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
On Thu, May 26, 2022 at 12:52PM +0200, Peter Zijlstra wrote:
> As x86 uses the <asm-generic/bitops/instrumented-*.h> headers, the
> regular forms of all bitops are instrumented with explicit calls to
> KASAN and KCSAN checks. As these are explicit calls, these are not
> suppressed by the noinstr function attribute.
>
> This can result in calls to those check functions in noinstr code, which
> objtool warns about:
>
> vmlinux.o: warning: objtool: enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x28: call to __kcsan_check_access() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x24: call to __kcsan_check_access() leaves .noinstr.text section
> vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x24: call to __kcsan_check_access() leaves .noinstr.text section
>
> Prevent this by using the arch_*() bitops, which are the underlying
> bitops without explciit instrumentation.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Link: https://lkml.kernel.org/r/20220502111216.290518605@infradead.org
Acked-by: Marco Elver <elver@google.com>
> ---
> arch/x86/include/asm/cpufeature.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -51,7 +51,7 @@ extern const char * const x86_power_flag
> extern const char * const x86_bug_flags[NBUGINTS*32];
>
> #define test_cpu_cap(c, bit) \
> - test_bit(bit, (unsigned long *)((c)->x86_capability))
> + arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
>
> /*
> * There are 32 bits/features in each mask word. The high bits
>
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 5/7] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
` (3 preceding siblings ...)
2022-05-26 10:52 ` [PATCH 4/7] x86/cpu: Elide KCSAN for cpu_has() and friends Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-30 13:20 ` Marco Elver
2022-05-26 10:52 ` [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack() Peter Zijlstra
2022-05-26 10:52 ` [PATCH 7/7] context_tracking: Always inline empty stubs Peter Zijlstra
6 siblings, 1 reply; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
When building x86_64 with JUMP_LABEL=n it's possible for
instrumentation to sneak into noinstr:
vmlinux.o: warning: objtool: exit_to_user_mode+0x14: call to static_key_count.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_exit_to_user_mode+0x2d: call to static_key_count.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_exit_to_user_mode+0x1b: call to static_key_count.constprop.0() leaves .noinstr.text section
Switch to arch_ prefixed atomic to avoid the explicit instrumentation.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/jump_label.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -256,9 +256,9 @@ extern void static_key_disable_cpuslocke
#include <linux/atomic.h>
#include <linux/bug.h>
-static inline int static_key_count(struct static_key *key)
+static __always_inline int static_key_count(struct static_key *key)
{
- return atomic_read(&key->enabled);
+ return arch_atomic_read(&key->enabled);
}
static __always_inline void jump_label_init(void)
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 5/7] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds
2022-05-26 10:52 ` [PATCH 5/7] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds Peter Zijlstra
@ 2022-05-30 13:20 ` Marco Elver
0 siblings, 0 replies; 21+ messages in thread
From: Marco Elver @ 2022-05-30 13:20 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, jbaron, rostedt, ardb, mark.rutland,
kernel test robot
On Thu, May 26, 2022 at 12:52PM +0200, Peter Zijlstra wrote:
> When building x86_64 with JUMP_LABEL=n it's possible for
> instrumentation to sneak into noinstr:
>
> vmlinux.o: warning: objtool: exit_to_user_mode+0x14: call to static_key_count.constprop.0() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_exit_to_user_mode+0x2d: call to static_key_count.constprop.0() leaves .noinstr.text section
> vmlinux.o: warning: objtool: irqentry_exit_to_user_mode+0x1b: call to static_key_count.constprop.0() leaves .noinstr.text section
>
> Switch to arch_ prefixed atomic to avoid the explicit instrumentation.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
> ---
> include/linux/jump_label.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> --- a/include/linux/jump_label.h
> +++ b/include/linux/jump_label.h
> @@ -256,9 +256,9 @@ extern void static_key_disable_cpuslocke
> #include <linux/atomic.h>
> #include <linux/bug.h>
>
> -static inline int static_key_count(struct static_key *key)
> +static __always_inline int static_key_count(struct static_key *key)
> {
> - return atomic_read(&key->enabled);
> + return arch_atomic_read(&key->enabled);
> }
>
> static __always_inline void jump_label_init(void)
>
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack()
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
` (4 preceding siblings ...)
2022-05-26 10:52 ` [PATCH 5/7] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-30 10:38 ` [tip: objtool/urgent] " tip-bot2 for Peter Zijlstra
2022-05-30 13:21 ` [PATCH 6/7] " Marco Elver
2022-05-26 10:52 ` [PATCH 7/7] context_tracking: Always inline empty stubs Peter Zijlstra
6 siblings, 2 replies; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland
Becaues GCC clearly lost it's marbles again...
vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/processor.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -559,7 +559,7 @@ static __always_inline void native_swapg
#endif
}
-static inline unsigned long current_top_of_stack(void)
+static __always_inline unsigned long current_top_of_stack(void)
{
/*
* We can't read directly from tss.sp0: sp0 on x86_32 is special in
@@ -569,7 +569,7 @@ static inline unsigned long current_top_
return this_cpu_read_stable(cpu_current_top_of_stack);
}
-static inline bool on_thread_stack(void)
+static __always_inline bool on_thread_stack(void)
{
return (unsigned long)(current_top_of_stack() -
current_stack_pointer) < THREAD_SIZE;
^ permalink raw reply [flat|nested] 21+ messages in thread* [tip: objtool/urgent] x86: Always inline on_thread_stack() and current_top_of_stack()
2022-05-26 10:52 ` [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack() Peter Zijlstra
@ 2022-05-30 10:38 ` tip-bot2 for Peter Zijlstra
2022-05-30 13:21 ` [PATCH 6/7] " Marco Elver
1 sibling, 0 replies; 21+ messages in thread
From: tip-bot2 for Peter Zijlstra @ 2022-05-30 10:38 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Peter Zijlstra (Intel), x86, linux-kernel
The following commit has been merged into the objtool/urgent branch of tip:
Commit-ID: 1894a4030582472336c2873cb07911ce67e0d14e
Gitweb: https://git.kernel.org/tip/1894a4030582472336c2873cb07911ce67e0d14e
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Sat, 07 May 2022 13:37:45 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 27 May 2022 12:34:44 +02:00
x86: Always inline on_thread_stack() and current_top_of_stack()
Becaues GCC clearly lost it's marbles again...
vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to current_top_of_stack() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220526105958.071435483@infradead.org
---
arch/x86/include/asm/processor.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 91d0f93..356308c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -559,7 +559,7 @@ static __always_inline void native_swapgs(void)
#endif
}
-static inline unsigned long current_top_of_stack(void)
+static __always_inline unsigned long current_top_of_stack(void)
{
/*
* We can't read directly from tss.sp0: sp0 on x86_32 is special in
@@ -569,7 +569,7 @@ static inline unsigned long current_top_of_stack(void)
return this_cpu_read_stable(cpu_current_top_of_stack);
}
-static inline bool on_thread_stack(void)
+static __always_inline bool on_thread_stack(void)
{
return (unsigned long)(current_top_of_stack() -
current_stack_pointer) < THREAD_SIZE;
^ permalink raw reply related [flat|nested] 21+ messages in thread* Re: [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack()
2022-05-26 10:52 ` [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack() Peter Zijlstra
2022-05-30 10:38 ` [tip: objtool/urgent] " tip-bot2 for Peter Zijlstra
@ 2022-05-30 13:21 ` Marco Elver
1 sibling, 0 replies; 21+ messages in thread
From: Marco Elver @ 2022-05-30 13:21 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, jbaron, rostedt, ardb, mark.rutland
On Thu, May 26, 2022 at 12:52PM +0200, Peter Zijlstra wrote:
> Becaues GCC clearly lost it's marbles again...
>
This must have been with some of the big sanitizers though, right?
> vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to on_thread_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to on_thread_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to on_thread_stack() leaves .noinstr.text section
>
> vmlinux.o: warning: objtool: enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x53: call to current_top_of_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x4e: call to current_top_of_stack() leaves .noinstr.text section
> vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x4e: call to current_top_of_stack() leaves .noinstr.text section
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
> ---
> arch/x86/include/asm/processor.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -559,7 +559,7 @@ static __always_inline void native_swapg
> #endif
> }
>
> -static inline unsigned long current_top_of_stack(void)
> +static __always_inline unsigned long current_top_of_stack(void)
> {
> /*
> * We can't read directly from tss.sp0: sp0 on x86_32 is special in
> @@ -569,7 +569,7 @@ static inline unsigned long current_top_
> return this_cpu_read_stable(cpu_current_top_of_stack);
> }
>
> -static inline bool on_thread_stack(void)
> +static __always_inline bool on_thread_stack(void)
> {
> return (unsigned long)(current_top_of_stack() -
> current_stack_pointer) < THREAD_SIZE;
>
>
^ permalink raw reply [flat|nested] 21+ messages in thread
* [PATCH 7/7] context_tracking: Always inline empty stubs
2022-05-26 10:52 [PATCH 0/7] x86: Address various objtool complaints Peter Zijlstra
` (5 preceding siblings ...)
2022-05-26 10:52 ` [PATCH 6/7] x86: Always inline on_thread_stack() and current_top_of_stack() Peter Zijlstra
@ 2022-05-26 10:52 ` Peter Zijlstra
2022-05-26 15:02 ` Josh Poimboeuf
2022-05-30 10:38 ` [tip: objtool/urgent] " tip-bot2 for Peter Zijlstra
6 siblings, 2 replies; 21+ messages in thread
From: Peter Zijlstra @ 2022-05-26 10:52 UTC (permalink / raw)
To: x86, jpoimboe
Cc: linux-kernel, peterz, elver, jbaron, rostedt, ardb, mark.rutland
Because GCC is seriously challenged..
vmlinux.o: warning: objtool: enter_from_user_mode+0x85: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x8f: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x85: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x85: call to context_tracking_enabled() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/context_tracking_state.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -46,10 +46,10 @@ static __always_inline bool context_trac
return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
}
#else
-static inline bool context_tracking_in_user(void) { return false; }
-static inline bool context_tracking_enabled(void) { return false; }
-static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
-static inline bool context_tracking_enabled_this_cpu(void) { return false; }
+static __always_inline bool context_tracking_in_user(void) { return false; }
+static __always_inline bool context_tracking_enabled(void) { return false; }
+static __always_inline bool context_tracking_enabled_cpu(int cpu) { return false; }
+static __always_inline bool context_tracking_enabled_this_cpu(void) { return false; }
#endif /* CONFIG_CONTEXT_TRACKING */
#endif
^ permalink raw reply [flat|nested] 21+ messages in thread* Re: [PATCH 7/7] context_tracking: Always inline empty stubs
2022-05-26 10:52 ` [PATCH 7/7] context_tracking: Always inline empty stubs Peter Zijlstra
@ 2022-05-26 15:02 ` Josh Poimboeuf
2022-05-26 15:10 ` Mark Rutland
2022-05-30 10:38 ` [tip: objtool/urgent] " tip-bot2 for Peter Zijlstra
1 sibling, 1 reply; 21+ messages in thread
From: Josh Poimboeuf @ 2022-05-26 15:02 UTC (permalink / raw)
To: Peter Zijlstra
Cc: x86, jpoimboe, linux-kernel, elver, jbaron, rostedt, ardb, mark.rutland
On Thu, May 26, 2022 at 12:52:59PM +0200, Peter Zijlstra wrote:
> Because GCC is seriously challenged..
Or are these CONFIG_DEBUG_SECTION_MISMATCH?
--
Josh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 7/7] context_tracking: Always inline empty stubs
2022-05-26 15:02 ` Josh Poimboeuf
@ 2022-05-26 15:10 ` Mark Rutland
2022-05-26 15:16 ` Josh Poimboeuf
0 siblings, 1 reply; 21+ messages in thread
From: Mark Rutland @ 2022-05-26 15:10 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Peter Zijlstra, x86, jpoimboe, linux-kernel, elver, jbaron,
rostedt, ardb
On Thu, May 26, 2022 at 08:02:06AM -0700, Josh Poimboeuf wrote:
> On Thu, May 26, 2022 at 12:52:59PM +0200, Peter Zijlstra wrote:
> > Because GCC is seriously challenged..
>
> Or are these CONFIG_DEBUG_SECTION_MISMATCH?
Does it matter?
The fact that CONFIG_DEBUG_SECTION_MISMATCH=y forces GCC to place these
out-of-line is really a debugging aid, since it shows us what it could
potentially leave out-of-line. It's not the *only* reason GCC might do this
(e.g. I see sanitizers and other debug options often have similar effects on
arm64).
So FWIW, for the patch:
Acked-by: Mark Rutland <mark.rutland@arm.com>
... as I'd like this for arm64, even if you don't beleive that's necessary for
x86.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 7/7] context_tracking: Always inline empty stubs
2022-05-26 15:10 ` Mark Rutland
@ 2022-05-26 15:16 ` Josh Poimboeuf
2022-05-26 15:26 ` Mark Rutland
0 siblings, 1 reply; 21+ messages in thread
From: Josh Poimboeuf @ 2022-05-26 15:16 UTC (permalink / raw)
To: Mark Rutland
Cc: Peter Zijlstra, x86, jpoimboe, linux-kernel, elver, jbaron,
rostedt, ardb
On Thu, May 26, 2022 at 04:10:52PM +0100, Mark Rutland wrote:
> On Thu, May 26, 2022 at 08:02:06AM -0700, Josh Poimboeuf wrote:
> > On Thu, May 26, 2022 at 12:52:59PM +0200, Peter Zijlstra wrote:
> > > Because GCC is seriously challenged..
> >
> > Or are these CONFIG_DEBUG_SECTION_MISMATCH?
>
> Does it matter?
Yes, because I believe the only thing this option is good for is
creating a bunch of useless '__always_inline' patches:
https://lore.kernel.org/all/7fad83ecde03540e65677959034315f8fbb3755e.1649434832.git.jpoimboe@redhat.com/
--
Josh
^ permalink raw reply [flat|nested] 21+ messages in thread
* Re: [PATCH 7/7] context_tracking: Always inline empty stubs
2022-05-26 15:16 ` Josh Poimboeuf
@ 2022-05-26 15:26 ` Mark Rutland
0 siblings, 0 replies; 21+ messages in thread
From: Mark Rutland @ 2022-05-26 15:26 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Peter Zijlstra, x86, jpoimboe, linux-kernel, elver, jbaron,
rostedt, ardb
On Thu, May 26, 2022 at 08:16:54AM -0700, Josh Poimboeuf wrote:
> On Thu, May 26, 2022 at 04:10:52PM +0100, Mark Rutland wrote:
> > On Thu, May 26, 2022 at 08:02:06AM -0700, Josh Poimboeuf wrote:
> > > On Thu, May 26, 2022 at 12:52:59PM +0200, Peter Zijlstra wrote:
> > > > Because GCC is seriously challenged..
> > >
> > > Or are these CONFIG_DEBUG_SECTION_MISMATCH?
> >
> > Does it matter?
>
> Yes, because I believe the only thing this option is good for is
> creating a bunch of useless '__always_inline' patches:
>
> https://lore.kernel.org/all/7fad83ecde03540e65677959034315f8fbb3755e.1649434832.git.jpoimboe@redhat.com/
Sure, but as I said, there are other reasons why the compiler can generate code
in this way, even if that's unlikely. Without `__always_inline` we don't
actually have a guarantee of inlining, so those warning *is* legitimate, even
if 99.99% of the time the compiler doesn't decide to generate code in a silly
way.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 21+ messages in thread
* [tip: objtool/urgent] context_tracking: Always inline empty stubs
2022-05-26 10:52 ` [PATCH 7/7] context_tracking: Always inline empty stubs Peter Zijlstra
2022-05-26 15:02 ` Josh Poimboeuf
@ 2022-05-30 10:38 ` tip-bot2 for Peter Zijlstra
1 sibling, 0 replies; 21+ messages in thread
From: tip-bot2 for Peter Zijlstra @ 2022-05-30 10:38 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Peter Zijlstra (Intel), Mark Rutland, x86, linux-kernel
The following commit has been merged into the objtool/urgent branch of tip:
Commit-ID: 620f8d3bd3d5e82dff8cc591c831827d4beeae2e
Gitweb: https://git.kernel.org/tip/620f8d3bd3d5e82dff8cc591c831827d4beeae2e
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Sat, 07 May 2022 13:35:37 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 27 May 2022 12:34:44 +02:00
context_tracking: Always inline empty stubs
Because GCC is seriously challenged..
vmlinux.o: warning: objtool: enter_from_user_mode+0x85: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0x8f: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0x85: call to context_tracking_enabled() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0x85: call to context_tracking_enabled() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20220526105958.134113388@infradead.org
---
include/linux/context_tracking_state.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
index 65a60d3..ae1e63e 100644
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -46,10 +46,10 @@ static __always_inline bool context_tracking_in_user(void)
return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
}
#else
-static inline bool context_tracking_in_user(void) { return false; }
-static inline bool context_tracking_enabled(void) { return false; }
-static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
-static inline bool context_tracking_enabled_this_cpu(void) { return false; }
+static __always_inline bool context_tracking_in_user(void) { return false; }
+static __always_inline bool context_tracking_enabled(void) { return false; }
+static __always_inline bool context_tracking_enabled_cpu(int cpu) { return false; }
+static __always_inline bool context_tracking_enabled_this_cpu(void) { return false; }
#endif /* CONFIG_CONTEXT_TRACKING */
#endif
^ permalink raw reply related [flat|nested] 21+ messages in thread