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- Allow the compiler to optimize away unused percpu accesses and change

Browse source 
the local_lock_* macros back to inline functions
 
 - A couple of fixes to static call insn patching
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Merge tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Borislav Petkov:

 - Allow the compiler to optimize away unused percpu accesses and change
   the local_lock_* macros back to inline functions

 - A couple of fixes to static call insn patching

* tag 'locking_urgent_for_v5.18_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "mm/page_alloc: mark pagesets as __maybe_unused"
  Revert "locking/local_lock: Make the empty local_lock_*() function a macro."
  x86/percpu: Remove volatile from arch_raw_cpu_ptr().
  static_call: Remove __DEFINE_STATIC_CALL macro
  static_call: Properly initialise DEFINE_STATIC_CALL_RET0()
  static_call: Don't make __static_call_return0 static
  x86,static_call: Fix __static_call_return0 for i386
This commit is contained in:
Linus Torvalds 2022-04-10 06:56:46 -10:00
commit 50c94de67c
10 changed files with 585 additions and 572 deletions
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1
arch/powerpc/include/asm/static_call.h
View file

@ -24,5 +24,6 @@
#define ARCH_DEFINE_STATIC_CALL_TRAMP(name, func) __PPC_SCT(name, "b " #func)
#define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) __PPC_SCT(name, "blr")
#define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name) __PPC_SCT(name, "b .+20")
#endif /* _ASM_POWERPC_STATIC_CALL_H */

6
arch/x86/include/asm/percpu.h
View file

@ -38,9 +38,9 @@
#define arch_raw_cpu_ptr(ptr) \
({ \
unsigned long tcp_ptr__; \
asm volatile("add " __percpu_arg(1) ", %0" \
: "=r" (tcp_ptr__) \
: "m" (this_cpu_off), "0" (ptr)); \
asm ("add " __percpu_arg(1) ", %0" \
: "=r" (tcp_ptr__) \
: "m" (this_cpu_off), "0" (ptr)); \
(typeof(*(ptr)) __kernel __force *)tcp_ptr__; \
})
#else

2
arch/x86/include/asm/static_call.h
View file

@ -38,6 +38,8 @@
#define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) \
__ARCH_DEFINE_STATIC_CALL_TRAMP(name, "ret; int3; nop; nop; nop")
#define ARCH_DEFINE_STATIC_CALL_RET0_TRAMP(name) \
ARCH_DEFINE_STATIC_CALL_TRAMP(name, __static_call_return0)
#define ARCH_ADD_TRAMP_KEY(name) \
asm(".pushsection .static_call_tramp_key, \"a\" \n" \

5
arch/x86/kernel/static_call.c
View file

@ -12,10 +12,9 @@ enum insn_type {
};
/*
* data16 data16 xorq %rax, %rax - a single 5 byte instruction that clears %rax
* The REX.W cancels the effect of any data16.
* cs cs cs xorl %eax, %eax - a single 5 byte instruction that clears %[er]ax
*/
static const u8 xor5rax[] = { 0x66, 0x66, 0x48, 0x31, 0xc0 };
static const u8 xor5rax[] = { 0x2e, 0x2e, 0x2e, 0x31, 0xc0 };
static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };