Masahiro Yamada
2018-Dec-17 16:03 UTC
[PATCH v3 00/12] x86, kbuild: revert macrofying inline assembly code
This series reverts the in-kernel workarounds for inlining issues.
The commit description of 77b0bf55bc67 mentioned
"We also hope that GCC will eventually get fixed,..."
Now, GCC provides a solution.
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html
explains the new "asm inline" syntax.
The performance issue will be eventually solved.
[About Code cleanups]
I know Nadam Amit is opposed to the full revert.
He also claims his motivation for macrofying was not only
performance, but also cleanups.
IIUC, the criticism addresses the code duplication between C and ASM.
If so, I'd like to suggest a different approach for cleanups.
Please see the last 3 patches.
IMHO, preprocessor approach is more straight-forward, and readable.
Basically, this idea should work because it is what we already do for
__ASM_FORM() etc.
[Quick Test of "asm inline" of GCC 9]
If you want to try "asm inline" feature, the patch is available:
https://lore.kernel.org/patchwork/patch/1024590/
The number of symbols for arch/x86/configs/x86_64_defconfig:
nr_symbols
[1] v4.20-rc7 : 96502
[2] [1]+full revert : 96705 (+203)
[3] [2]+"asm inline": 96568 (-137)
[3]: apply my patch, then replace "asm" -> "asm_inline"
for _BUG_FLAGS(), refcount_add(), refcount_inc(), refcount_dec(),
annotate_reachable(), annotate_unreachable()
Changes in v3:
- Split into per-commit revert (per Nadav Amit)
- Add some cleanups with preprocessor approach
Changes in v2:
- Revive clean-ups made by 5bdcd510c2ac (per Peter Zijlstra)
- Fix commit quoting style (per Peter Zijlstra)
Masahiro Yamada (12):
Revert "x86/jump-labels: Macrofy inline assembly code to work around
GCC inlining bugs"
Revert "x86/cpufeature: Macrofy inline assembly code to work around
GCC inlining bugs"
Revert "x86/extable: Macrofy inline assembly code to work around GCC
inlining bugs"
Revert "x86/paravirt: Work around GCC inlining bugs when compiling
paravirt ops"
Revert "x86/bug: Macrofy the BUG table section handling, to work
around GCC inlining bugs"
Revert "x86/alternatives: Macrofy lock prefixes to work around GCC
inlining bugs"
Revert "x86/refcount: Work around GCC inlining bug"
Revert "x86/objtool: Use asm macros to work around GCC inlining
bugs"
Revert "kbuild/Makefile: Prepare for using macros in inline assembly
code to work around asm() related GCC inlining bugs"
linux/linkage: add ASM() macro to reduce duplication between C/ASM
code
x86/alternatives: consolidate LOCK_PREFIX macro
x86/asm: consolidate ASM_EXTABLE_* macros
Makefile | 9 +--
arch/x86/Makefile | 7 ---
arch/x86/include/asm/alternative-asm.h | 22 +------
arch/x86/include/asm/alternative-common.h | 47 +++++++++++++++
arch/x86/include/asm/alternative.h | 30 +---------
arch/x86/include/asm/asm.h | 46 +++++----------
arch/x86/include/asm/bug.h | 98 +++++++++++++------------------
arch/x86/include/asm/cpufeature.h | 82 +++++++++++---------------
arch/x86/include/asm/jump_label.h | 22 +++++--
arch/x86/include/asm/paravirt_types.h | 56 +++++++++---------
arch/x86/include/asm/refcount.h | 81 +++++++++++--------------
arch/x86/kernel/macros.S | 16 -----
include/asm-generic/bug.h | 8 +--
include/linux/compiler.h | 56 ++++--------------
include/linux/linkage.h | 8 +++
scripts/Kbuild.include | 4 +-
scripts/mod/Makefile | 2 -
17 files changed, 249 insertions(+), 345 deletions(-)
create mode 100644 arch/x86/include/asm/alternative-common.h
delete mode 100644 arch/x86/kernel/macros.S
--
2.7.4
Masahiro Yamada
2018-Dec-17 16:03 UTC
[PATCH v3 04/12] Revert "x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops"
This reverts commit 494b5168f2de009eb80f198f668da374295098dd.
The in-kernel workarounds will be replaced with GCC's new
"asm inline" syntax.
Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
---
arch/x86/include/asm/paravirt_types.h | 56 ++++++++++++++++++-----------------
arch/x86/kernel/macros.S | 1 -
2 files changed, 29 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h
b/arch/x86/include/asm/paravirt_types.h
index 26942ad..488c596 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -348,11 +348,23 @@ extern struct paravirt_patch_template pv_ops;
#define paravirt_clobber(clobber) \
[paravirt_clobber] "i" (clobber)
+/*
+ * Generate some code, and mark it as patchable by the
+ * apply_paravirt() alternate instruction patcher.
+ */
+#define _paravirt_alt(insn_string, type, clobber) \
+ "771:\n\t" insn_string "\n" "772:\n" \
+ ".pushsection .parainstructions,\"a\"\n" \
+ _ASM_ALIGN "\n" \
+ _ASM_PTR " 771b\n" \
+ " .byte " type "\n" \
+ " .byte 772b-771b\n" \
+ " .short " clobber "\n" \
+ ".popsection\n"
+
/* Generate patchable code, with the default asm parameters. */
-#define paravirt_call \
- "PARAVIRT_CALL type=\"%c[paravirt_typenum]\"" \
- " clobber=\"%c[paravirt_clobber]\"" \
- " pv_opptr=\"%c[paravirt_opptr]\";"
+#define paravirt_alt(insn_string) \
+ _paravirt_alt(insn_string, "%c[paravirt_typenum]",
"%c[paravirt_clobber]")
/* Simple instruction patching code. */
#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b
"\n" a #x "_" #b ":\n\t"
@@ -373,6 +385,16 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long
addr, unsigned len);
int paravirt_disable_iospace(void);
/*
+ * This generates an indirect call based on the operation type number.
+ * The type number, computed in PARAVIRT_PATCH, is derived from the
+ * offset into the paravirt_patch_template structure, and can therefore be
+ * freely converted back into a structure offset.
+ */
+#define PARAVIRT_CALL \
+ ANNOTATE_RETPOLINE_SAFE \
+ "call *%c[paravirt_opptr];"
+
+/*
* These macros are intended to wrap calls through one of the paravirt
* ops structs, so that they can be later identified and patched at
* runtime.
@@ -509,7 +531,7 @@ int paravirt_disable_iospace(void);
/* since this condition will never hold */ \
if (sizeof(rettype) > sizeof(unsigned long)) { \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -519,7 +541,7 @@ int paravirt_disable_iospace(void);
__ret = (rettype)((((u64)__edx) << 32) | __eax); \
} else { \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -546,7 +568,7 @@ int paravirt_disable_iospace(void);
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -664,26 +686,6 @@ struct paravirt_patch_site {
extern struct paravirt_patch_site __parainstructions[],
__parainstructions_end[];
-#else /* __ASSEMBLY__ */
-
-/*
- * This generates an indirect call based on the operation type number.
- * The type number, computed in PARAVIRT_PATCH, is derived from the
- * offset into the paravirt_patch_template structure, and can therefore be
- * freely converted back into a structure offset.
- */
-.macro PARAVIRT_CALL type:req clobber:req pv_opptr:req
-771: ANNOTATE_RETPOLINE_SAFE
- call *\pv_opptr
-772: .pushsection .parainstructions,"a"
- _ASM_ALIGN
- _ASM_PTR 771b
- .byte \type
- .byte 772b-771b
- .short \clobber
- .popsection
-.endm
-
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_PARAVIRT_TYPES_H */
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
index 71d8b71..66ccb8e 100644
--- a/arch/x86/kernel/macros.S
+++ b/arch/x86/kernel/macros.S
@@ -10,4 +10,3 @@
#include <asm/refcount.h>
#include <asm/alternative-asm.h>
#include <asm/bug.h>
-#include <asm/paravirt.h>
--
2.7.4
Ingo Molnar
2018-Dec-19 11:20 UTC
[PATCH v3 00/12] x86, kbuild: revert macrofying inline assembly code
* Masahiro Yamada <yamada.masahiro at socionext.com> wrote:> This series reverts the in-kernel workarounds for inlining issues. > > The commit description of 77b0bf55bc67 mentioned > "We also hope that GCC will eventually get fixed,..." > > Now, GCC provides a solution. > > https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html > explains the new "asm inline" syntax. > > The performance issue will be eventually solved. > > [About Code cleanups] > > I know Nadam Amit is opposed to the full revert. > He also claims his motivation for macrofying was not only > performance, but also cleanups. > > IIUC, the criticism addresses the code duplication between C and ASM. > > If so, I'd like to suggest a different approach for cleanups. > Please see the last 3 patches. > IMHO, preprocessor approach is more straight-forward, and readable. > Basically, this idea should work because it is what we already do for > __ASM_FORM() etc. > > [Quick Test of "asm inline" of GCC 9] > > If you want to try "asm inline" feature, the patch is available: > https://lore.kernel.org/patchwork/patch/1024590/ > > The number of symbols for arch/x86/configs/x86_64_defconfig: > > nr_symbols > [1] v4.20-rc7 : 96502 > [2] [1]+full revert : 96705 (+203) > [3] [2]+"asm inline": 96568 (-137) > > [3]: apply my patch, then replace "asm" -> "asm_inline" > for _BUG_FLAGS(), refcount_add(), refcount_inc(), refcount_dec(), > annotate_reachable(), annotate_unreachable() > > > Changes in v3: > - Split into per-commit revert (per Nadav Amit) > - Add some cleanups with preprocessor approach > > Changes in v2: > - Revive clean-ups made by 5bdcd510c2ac (per Peter Zijlstra) > - Fix commit quoting style (per Peter Zijlstra) > > Masahiro Yamada (12): > Revert "x86/jump-labels: Macrofy inline assembly code to work around > GCC inlining bugs" > Revert "x86/cpufeature: Macrofy inline assembly code to work around > GCC inlining bugs" > Revert "x86/extable: Macrofy inline assembly code to work around GCC > inlining bugs" > Revert "x86/paravirt: Work around GCC inlining bugs when compiling > paravirt ops" > Revert "x86/bug: Macrofy the BUG table section handling, to work > around GCC inlining bugs" > Revert "x86/alternatives: Macrofy lock prefixes to work around GCC > inlining bugs" > Revert "x86/refcount: Work around GCC inlining bug" > Revert "x86/objtool: Use asm macros to work around GCC inlining bugs" > Revert "kbuild/Makefile: Prepare for using macros in inline assembly > code to work around asm() related GCC inlining bugs" > linux/linkage: add ASM() macro to reduce duplication between C/ASM > code > x86/alternatives: consolidate LOCK_PREFIX macro > x86/asm: consolidate ASM_EXTABLE_* macros > > Makefile | 9 +-- > arch/x86/Makefile | 7 --- > arch/x86/include/asm/alternative-asm.h | 22 +------ > arch/x86/include/asm/alternative-common.h | 47 +++++++++++++++ > arch/x86/include/asm/alternative.h | 30 +--------- > arch/x86/include/asm/asm.h | 46 +++++---------- > arch/x86/include/asm/bug.h | 98 +++++++++++++------------------ > arch/x86/include/asm/cpufeature.h | 82 +++++++++++--------------- > arch/x86/include/asm/jump_label.h | 22 +++++-- > arch/x86/include/asm/paravirt_types.h | 56 +++++++++--------- > arch/x86/include/asm/refcount.h | 81 +++++++++++-------------- > arch/x86/kernel/macros.S | 16 ----- > include/asm-generic/bug.h | 8 +-- > include/linux/compiler.h | 56 ++++-------------- > include/linux/linkage.h | 8 +++ > scripts/Kbuild.include | 4 +- > scripts/mod/Makefile | 2 - > 17 files changed, 249 insertions(+), 345 deletions(-) > create mode 100644 arch/x86/include/asm/alternative-common.h > delete mode 100644 arch/x86/kernel/macros.SI absolutely agree that this needs to be resolved in v4.20. So I did the 1-9 reverts manually myself as well, because I think the first commit should be reverted fully to get as close to the starting point as possible (we are late in the cycle) - and came to the attached interdiff between your series and mine. Does this approach look OK to you, or did I miss something? Thanks, Ingo =============> entry/calling.h | 2 - include/asm/jump_label.h | 50 ++++++++++++++++++++++++++++++++++------------- 2 files changed, 38 insertions(+), 14 deletions(-) diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 25e5a6bda8c3..20d0885b00fb 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -352,7 +352,7 @@ For 32-bit we have the following conventions - kernel is built with .macro CALL_enter_from_user_mode #ifdef CONFIG_CONTEXT_TRACKING #ifdef HAVE_JUMP_LABEL - STATIC_BRANCH_JMP l_yes=.Lafter_call_\@, key=context_tracking_enabled, branch=1 + STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0 #endif call enter_from_user_mode .Lafter_call_\@: diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index cf88ebf9a4ca..21efc9d07ed9 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -2,6 +2,19 @@ #ifndef _ASM_X86_JUMP_LABEL_H #define _ASM_X86_JUMP_LABEL_H +#ifndef HAVE_JUMP_LABEL +/* + * For better or for worse, if jump labels (the gcc extension) are missing, + * then the entire static branch patching infrastructure is compiled out. + * If that happens, the code in here will malfunction. Raise a compiler + * error instead. + * + * In theory, jump labels and the static branch patching infrastructure + * could be decoupled to fix this. + */ +#error asm/jump_label.h included on a non-jump-label kernel +#endif + #define JUMP_LABEL_NOP_SIZE 5 #ifdef CONFIG_X86_64 @@ -53,26 +66,37 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key, bool #else /* __ASSEMBLY__ */ -.macro STATIC_BRANCH_NOP l_yes:req key:req branch:req -.Lstatic_branch_nop_\@: - .byte STATIC_KEY_INIT_NOP -.Lstatic_branch_no_after_\@: +.macro STATIC_JUMP_IF_TRUE target, key, def +.Lstatic_jump_\@: + .if \def + /* Equivalent to "jmp.d32 \target" */ + .byte 0xe9 + .long \target - .Lstatic_jump_after_\@ +.Lstatic_jump_after_\@: + .else + .byte STATIC_KEY_INIT_NOP + .endif .pushsection __jump_table, "aw" _ASM_ALIGN - .long .Lstatic_branch_nop_\@ - ., \l_yes - . - _ASM_PTR \key + \branch - . + .long .Lstatic_jump_\@ - ., \target - . + _ASM_PTR \key - . .popsection .endm -.macro STATIC_BRANCH_JMP l_yes:req key:req branch:req -.Lstatic_branch_jmp_\@: - .byte 0xe9 - .long \l_yes - .Lstatic_branch_jmp_after_\@ -.Lstatic_branch_jmp_after_\@: +.macro STATIC_JUMP_IF_FALSE target, key, def +.Lstatic_jump_\@: + .if \def + .byte STATIC_KEY_INIT_NOP + .else + /* Equivalent to "jmp.d32 \target" */ + .byte 0xe9 + .long \target - .Lstatic_jump_after_\@ +.Lstatic_jump_after_\@: + .endif .pushsection __jump_table, "aw" _ASM_ALIGN - .long .Lstatic_branch_jmp_\@ - ., \l_yes - . - _ASM_PTR \key + \branch - . + .long .Lstatic_jump_\@ - ., \target - . + _ASM_PTR \key + 1 - . .popsection .endm
Masahiro Yamada
2018-Dec-19 14:33 UTC
[PATCH v3 00/12] x86, kbuild: revert macrofying inline assembly code
On Wed, Dec 19, 2018 at 9:44 PM Ingo Molnar <mingo at kernel.org> wrote:> > > * Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > > > This series reverts the in-kernel workarounds for inlining issues. > > > > The commit description of 77b0bf55bc67 mentioned > > "We also hope that GCC will eventually get fixed,..." > > > > Now, GCC provides a solution. > > > > https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html > > explains the new "asm inline" syntax. > > > > The performance issue will be eventually solved. > > > > [About Code cleanups] > > > > I know Nadam Amit is opposed to the full revert. > > He also claims his motivation for macrofying was not only > > performance, but also cleanups. > > > > IIUC, the criticism addresses the code duplication between C and ASM. > > > > If so, I'd like to suggest a different approach for cleanups. > > Please see the last 3 patches. > > IMHO, preprocessor approach is more straight-forward, and readable. > > Basically, this idea should work because it is what we already do for > > __ASM_FORM() etc. > > > > [Quick Test of "asm inline" of GCC 9] > > > > If you want to try "asm inline" feature, the patch is available: > > https://lore.kernel.org/patchwork/patch/1024590/ > > > > The number of symbols for arch/x86/configs/x86_64_defconfig: > > > > nr_symbols > > [1] v4.20-rc7 : 96502 > > [2] [1]+full revert : 96705 (+203) > > [3] [2]+"asm inline": 96568 (-137) > > > > [3]: apply my patch, then replace "asm" -> "asm_inline" > > for _BUG_FLAGS(), refcount_add(), refcount_inc(), refcount_dec(), > > annotate_reachable(), annotate_unreachable() > > > > > > Changes in v3: > > - Split into per-commit revert (per Nadav Amit) > > - Add some cleanups with preprocessor approach > > > > Changes in v2: > > - Revive clean-ups made by 5bdcd510c2ac (per Peter Zijlstra) > > - Fix commit quoting style (per Peter Zijlstra) > > > > Masahiro Yamada (12): > > Revert "x86/jump-labels: Macrofy inline assembly code to work around > > GCC inlining bugs" > > Revert "x86/cpufeature: Macrofy inline assembly code to work around > > GCC inlining bugs" > > Revert "x86/extable: Macrofy inline assembly code to work around GCC > > inlining bugs" > > Revert "x86/paravirt: Work around GCC inlining bugs when compiling > > paravirt ops" > > Revert "x86/bug: Macrofy the BUG table section handling, to work > > around GCC inlining bugs" > > Revert "x86/alternatives: Macrofy lock prefixes to work around GCC > > inlining bugs" > > Revert "x86/refcount: Work around GCC inlining bug" > > Revert "x86/objtool: Use asm macros to work around GCC inlining bugs" > > Revert "kbuild/Makefile: Prepare for using macros in inline assembly > > code to work around asm() related GCC inlining bugs" > > linux/linkage: add ASM() macro to reduce duplication between C/ASM > > code > > x86/alternatives: consolidate LOCK_PREFIX macro > > x86/asm: consolidate ASM_EXTABLE_* macros > > > > Makefile | 9 +-- > > arch/x86/Makefile | 7 --- > > arch/x86/include/asm/alternative-asm.h | 22 +------ > > arch/x86/include/asm/alternative-common.h | 47 +++++++++++++++ > > arch/x86/include/asm/alternative.h | 30 +--------- > > arch/x86/include/asm/asm.h | 46 +++++---------- > > arch/x86/include/asm/bug.h | 98 +++++++++++++------------------ > > arch/x86/include/asm/cpufeature.h | 82 +++++++++++--------------- > > arch/x86/include/asm/jump_label.h | 22 +++++-- > > arch/x86/include/asm/paravirt_types.h | 56 +++++++++--------- > > arch/x86/include/asm/refcount.h | 81 +++++++++++-------------- > > arch/x86/kernel/macros.S | 16 ----- > > include/asm-generic/bug.h | 8 +-- > > include/linux/compiler.h | 56 ++++-------------- > > include/linux/linkage.h | 8 +++ > > scripts/Kbuild.include | 4 +- > > scripts/mod/Makefile | 2 - > > 17 files changed, 249 insertions(+), 345 deletions(-) > > create mode 100644 arch/x86/include/asm/alternative-common.h > > delete mode 100644 arch/x86/kernel/macros.S > > I absolutely agree that this needs to be resolved in v4.20. > > So I did the 1-9 reverts manually myself as well, because I think the > first commit should be reverted fully to get as close to the starting > point as possible (we are late in the cycle) - and came to the attached > interdiff between your series and mine. > > Does this approach look OK to you, or did I miss something?It looks OK to me. I thought the diff was a good cleanup part, but we can deal with it later on, so I do not mind it. Thanks!> Thanks, > > Ingo > > =============> > > entry/calling.h | 2 - > include/asm/jump_label.h | 50 ++++++++++++++++++++++++++++++++++------------- > 2 files changed, 38 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h > index 25e5a6bda8c3..20d0885b00fb 100644 > --- a/arch/x86/entry/calling.h > +++ b/arch/x86/entry/calling.h > @@ -352,7 +352,7 @@ For 32-bit we have the following conventions - kernel is built with > .macro CALL_enter_from_user_mode > #ifdef CONFIG_CONTEXT_TRACKING > #ifdef HAVE_JUMP_LABEL > - STATIC_BRANCH_JMP l_yes=.Lafter_call_\@, key=context_tracking_enabled, branch=1 > + STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0 > #endif > call enter_from_user_mode > .Lafter_call_\@: > diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h > index cf88ebf9a4ca..21efc9d07ed9 100644 > --- a/arch/x86/include/asm/jump_label.h > +++ b/arch/x86/include/asm/jump_label.h > @@ -2,6 +2,19 @@ > #ifndef _ASM_X86_JUMP_LABEL_H > #define _ASM_X86_JUMP_LABEL_H > > +#ifndef HAVE_JUMP_LABEL > +/* > + * For better or for worse, if jump labels (the gcc extension) are missing, > + * then the entire static branch patching infrastructure is compiled out. > + * If that happens, the code in here will malfunction. Raise a compiler > + * error instead. > + * > + * In theory, jump labels and the static branch patching infrastructure > + * could be decoupled to fix this. > + */ > +#error asm/jump_label.h included on a non-jump-label kernel > +#endif > + > #define JUMP_LABEL_NOP_SIZE 5 > > #ifdef CONFIG_X86_64 > @@ -53,26 +66,37 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key, bool > > #else /* __ASSEMBLY__ */ > > -.macro STATIC_BRANCH_NOP l_yes:req key:req branch:req > -.Lstatic_branch_nop_\@: > - .byte STATIC_KEY_INIT_NOP > -.Lstatic_branch_no_after_\@: > +.macro STATIC_JUMP_IF_TRUE target, key, def > +.Lstatic_jump_\@: > + .if \def > + /* Equivalent to "jmp.d32 \target" */ > + .byte 0xe9 > + .long \target - .Lstatic_jump_after_\@ > +.Lstatic_jump_after_\@: > + .else > + .byte STATIC_KEY_INIT_NOP > + .endif > .pushsection __jump_table, "aw" > _ASM_ALIGN > - .long .Lstatic_branch_nop_\@ - ., \l_yes - . > - _ASM_PTR \key + \branch - . > + .long .Lstatic_jump_\@ - ., \target - . > + _ASM_PTR \key - . > .popsection > .endm > > -.macro STATIC_BRANCH_JMP l_yes:req key:req branch:req > -.Lstatic_branch_jmp_\@: > - .byte 0xe9 > - .long \l_yes - .Lstatic_branch_jmp_after_\@ > -.Lstatic_branch_jmp_after_\@: > +.macro STATIC_JUMP_IF_FALSE target, key, def > +.Lstatic_jump_\@: > + .if \def > + .byte STATIC_KEY_INIT_NOP > + .else > + /* Equivalent to "jmp.d32 \target" */ > + .byte 0xe9 > + .long \target - .Lstatic_jump_after_\@ > +.Lstatic_jump_after_\@: > + .endif > .pushsection __jump_table, "aw" > _ASM_ALIGN > - .long .Lstatic_branch_jmp_\@ - ., \l_yes - . > - _ASM_PTR \key + \branch - . > + .long .Lstatic_jump_\@ - ., \target - . > + _ASM_PTR \key + 1 - . > .popsection > .endm > >-- Best Regards Masahiro Yamada
Apparently Analagous Threads
- [PATCH 08/13] x86/paravirt: Clean up paravirt_types.h
- [PATCH v2] x86, kbuild: revert macrofying inline assembly code
- [PATCH] kbuild, x86: revert macros in extended asm workarounds
- [PATCH] kbuild, x86: revert macros in extended asm workarounds
- [PATCH 07/13] x86/paravirt: Simplify ____PVOP_CALL()