git: ab92c99aa56f - main - i386 pcpu: fix clobbers, suppress warnings, and clean up
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Date: Wed, 03 Jul 2024 16:14:56 UTC
The branch main has been updated by rlibby: URL: https://cgit.FreeBSD.org/src/commit/?id=ab92c99aa56fdec4a06f9af5f30f87ef08fbeb0e commit ab92c99aa56fdec4a06f9af5f30f87ef08fbeb0e Author: Ryan Libby <rlibby@FreeBSD.org> AuthorDate: 2024-07-03 15:35:31 +0000 Commit: Ryan Libby <rlibby@FreeBSD.org> CommitDate: 2024-07-03 15:35:31 +0000 i386 pcpu: fix clobbers, suppress warnings, and clean up - Add missing cc clobber to __PCPU_ADD (which is currently unused). - Allow the compiler the opportunity to marginally improve code generation from __PCPU_PTR by letting it figure out how to do the add (also removing the addition fixes a missing cc clobber). - Quiet gcc -Warray-bounds by using constant operands instead of bogus memory references. - Remove the struct __s __s temporaries, just cast through the type. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D45826 --- sys/i386/include/pcpu.h | 47 +++++++++++++++++++-------------------------- sys/i386/include/pcpu_aux.h | 8 ++++---- 2 files changed, 24 insertions(+), 31 deletions(-) diff --git a/sys/i386/include/pcpu.h b/sys/i386/include/pcpu.h index ef3f5cc9dff7..d51763b20798 100644 --- a/sys/i386/include/pcpu.h +++ b/sys/i386/include/pcpu.h @@ -108,16 +108,8 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line"); /* * Evaluates to the address of the per-cpu variable name. */ -#define __PCPU_PTR(name) __extension__ ({ \ - __pcpu_type(name) *__p; \ - \ - __asm __volatile("movl %%fs:%1,%0; addl %2,%0" \ - : "=r" (__p) \ - : "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace))), \ - "i" (__pcpu_offset(name))); \ - \ - __p; \ -}) +#define __PCPU_PTR(name) \ + (&get_pcpu()->name) /* * Evaluates to the value of the per-cpu variable name. @@ -126,14 +118,13 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line"); __pcpu_type(name) __res; \ struct __s { \ u_char __b[MIN(sizeof(__res), 4)]; \ - } __s; \ + }; \ \ if (sizeof(__res) == 1 || sizeof(__res) == 2 || \ sizeof(__res) == 4) { \ - __asm __volatile("mov %%fs:%1,%0" \ - : "=r" (__s) \ - : "m" (*(struct __s *)(__pcpu_offset(name)))); \ - *(struct __s *)(void *)&__res = __s; \ + __asm __volatile("mov %%fs:%c1,%0" \ + : "=r" (*(struct __s *)(void *)&__res) \ + : "i" (__pcpu_offset(name))); \ } else { \ __res = *__PCPU_PTR(name); \ } \ @@ -148,15 +139,16 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line"); __pcpu_type(name) __val; \ struct __s { \ u_char __b[MIN(sizeof(__val), 4)]; \ - } __s; \ + }; \ \ __val = (val); \ if (sizeof(__val) == 1 || sizeof(__val) == 2 || \ sizeof(__val) == 4) { \ - __s = *(struct __s *)(void *)&__val; \ - __asm __volatile("add %1,%%fs:%0" \ - : "=m" (*(struct __s *)(__pcpu_offset(name))) \ - : "r" (__s)); \ + __asm __volatile("add %1,%%fs:%c0" \ + : \ + : "i" (__pcpu_offset(name)), \ + "r" (*(struct __s *)(void *)&__val) \ + : "cc", "memory"); \ } else \ *__PCPU_PTR(name) += __val; \ } while (0) @@ -168,15 +160,16 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line"); __pcpu_type(name) __val; \ struct __s { \ u_char __b[MIN(sizeof(__val), 4)]; \ - } __s; \ + }; \ \ __val = (val); \ if (sizeof(__val) == 1 || sizeof(__val) == 2 || \ sizeof(__val) == 4) { \ - __s = *(struct __s *)(void *)&__val; \ - __asm __volatile("mov %1,%%fs:%0" \ - : "=m" (*(struct __s *)(__pcpu_offset(name))) \ - : "r" (__s)); \ + __asm __volatile("mov %1,%%fs:%c0" \ + : \ + : "i" (__pcpu_offset(name)), \ + "r" (*(struct __s *)(void *)&__val) \ + : "memory"); \ } else { \ *__PCPU_PTR(name) = __val; \ } \ @@ -185,9 +178,9 @@ _Static_assert(sizeof(struct monitorbuf) == 128, "2x cache line"); #define get_pcpu() __extension__ ({ \ struct pcpu *__pc; \ \ - __asm __volatile("movl %%fs:%1,%0" \ + __asm __volatile("movl %%fs:%c1,%0" \ : "=r" (__pc) \ - : "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace)))); \ + : "i" (__pcpu_offset(pc_prvspace))); \ __pc; \ }) diff --git a/sys/i386/include/pcpu_aux.h b/sys/i386/include/pcpu_aux.h index 9d15ee1f3ee3..a38faf9af964 100644 --- a/sys/i386/include/pcpu_aux.h +++ b/sys/i386/include/pcpu_aux.h @@ -49,8 +49,8 @@ __curthread(void) { struct thread *td; - __asm("movl %%fs:%1,%0" : "=r" (td) - : "m" (*(char *)offsetof(struct pcpu, pc_curthread))); + __asm("movl %%fs:%c1,%0" : "=r" (td) + : "i" (offsetof(struct pcpu, pc_curthread))); return (td); } #define curthread (__curthread()) @@ -60,8 +60,8 @@ __curpcb(void) { struct pcb *pcb; - __asm("movl %%fs:%1,%0" : "=r" (pcb) - : "m" (*(char *)offsetof(struct pcpu, pc_curpcb))); + __asm("movl %%fs:%c1,%0" : "=r" (pcb) + : "i" (offsetof(struct pcpu, pc_curpcb))); return (pcb); } #define curpcb (__curpcb())