From: Uros Bizjak Date: Sun, 17 Aug 2025 15:50:47 +0000 (+0200) Subject: i386: Use __seg_gs qualifiers in NPTL accessors X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0e49fc68aa1200eb20d13648f084122b2d65f908;p=thirdparty%2Fglibc.git i386: Use __seg_gs qualifiers in NPTL accessors Use __seg_gs named address space qualifiers to cast NPTL accessors to %gs: prefixed addresses. Use volatile access only where strictly necessary. Signed-off-by: Uros Bizjak Cc: H.J.Lu Cc: Florian Weimer Cc: Carlos O'Donell Reviewed-by: H.J. Lu --- diff --git a/sysdeps/i386/nptl/rseq-access.h b/sysdeps/i386/nptl/rseq-access.h index 5e7e09d494..ee78c6198d 100644 --- a/sysdeps/i386/nptl/rseq-access.h +++ b/sysdeps/i386/nptl/rseq-access.h @@ -16,28 +16,6 @@ License along with the GNU C Library; if not, see . */ -#define __RSEQ_GETMEM(member) \ - ({ __typeof (RSEQ_SELF()->member) __value; \ - if (sizeof (__value) == 1) \ - asm volatile ("movb %%gs:%P2(%3),%b0" \ - : "=q" (__value) \ - : "0" (0), "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - else if (sizeof (__value) == 4) \ - asm volatile ("movl %%gs:%P1(%2),%0" \ - : "=r" (__value) \ - : "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%gs:%P1(%2),%%eax\n\t" \ - "movl %%gs:4+%P1(%2),%%edx" \ - : "=&A" (__value) \ - : "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - } \ - __value; }) - /* Read member of the RSEQ area directly. */ #define RSEQ_GETMEM(member) \ ({ \ @@ -45,7 +23,9 @@ || sizeof (RSEQ_SELF()->member) == 4 \ || sizeof (RSEQ_SELF()->member) == 8, \ "size of rseq data"); \ - __RSEQ_GETMEM(member); }) + (*(__typeof (RSEQ_SELF()->member) __seg_gs *) \ + (__rseq_offset + offsetof (struct rseq_area, member))); \ + }) /* Read member of the RSEQ area directly, with single-copy atomicity semantics. Static assert for types >= 64 bits since they can't be loaded atomically on @@ -55,28 +35,9 @@ _Static_assert (sizeof (RSEQ_SELF()->member) == 1 \ || sizeof (RSEQ_SELF()->member) == 4, \ "size of rseq data"); \ - __RSEQ_GETMEM(member); }) - -#define __RSEQ_SETMEM(member, value) \ - ({ \ - if (sizeof (RSEQ_SELF()->member) == 1) \ - asm volatile ("movb %b0,%%gs:%P1(%2)" : \ - : "iq" (value), \ - "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - else if (sizeof (RSEQ_SELF()->member) == 4) \ - asm volatile ("movl %0,%%gs:%P1(%2)" : \ - : "ir" (value), \ - "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%eax,%%gs:%P1(%2)\n\t" \ - "movl %%edx,%%gs:4+%P1(%2)" : \ - : "A" ((uint64_t) cast_to_integer (value)), \ - "i" (offsetof (struct rseq_area, member)), \ - "r" (__rseq_offset)); \ - }}) + (*(volatile __typeof (RSEQ_SELF()->member) __seg_gs *) \ + (__rseq_offset + offsetof (struct rseq_area, member))); \ + }) /* Set member of the RSEQ area directly. */ #define RSEQ_SETMEM(member, value) \ @@ -85,7 +46,9 @@ || sizeof (RSEQ_SELF()->member) == 4 \ || sizeof (RSEQ_SELF()->member) == 8, \ "size of rseq data"); \ - __RSEQ_SETMEM(member, value); }) + (*(__typeof (RSEQ_SELF()->member) __seg_gs *) \ + (__rseq_offset + offsetof (struct rseq_area, member)) = (value)); \ + }) /* Set member of the RSEQ area directly, with single-copy atomicity semantics. Static assert for types >= 64 bits since they can't be stored atomically on @@ -95,4 +58,6 @@ _Static_assert (sizeof (RSEQ_SELF()->member) == 1 \ || sizeof (RSEQ_SELF()->member) == 4, \ "size of rseq data"); \ - __RSEQ_SETMEM(member, value); }) + (*(volatile __typeof (RSEQ_SELF()->member) __seg_gs *) \ + (__rseq_offset + offsetof (struct rseq_area, member)) = (value)); \ + }) diff --git a/sysdeps/i386/nptl/tcb-access.h b/sysdeps/i386/nptl/tcb-access.h index dc84dfeef4..2a7f9d2a57 100644 --- a/sysdeps/i386/nptl/tcb-access.h +++ b/sysdeps/i386/nptl/tcb-access.h @@ -18,60 +18,35 @@ /* Read member of the thread descriptor directly. */ #define THREAD_GETMEM(descr, member) \ - ({ __typeof (descr->member) __value; \ - _Static_assert (sizeof (__value) == 1 \ - || sizeof (__value) == 4 \ - || sizeof (__value) == 8, \ + ({ \ + _Static_assert (sizeof (descr->member) == 1 \ + || sizeof (descr->member) == 4 \ + || sizeof (descr->member) == 8, \ "size of per-thread data"); \ - if (sizeof (__value) == 1) \ - asm volatile ("movb %%gs:%P2,%b0" \ - : "=q" (__value) \ - : "0" (0), "i" (offsetof (struct pthread, member))); \ - else if (sizeof (__value) == 4) \ - asm volatile ("movl %%gs:%P1,%0" \ - : "=r" (__value) \ - : "i" (offsetof (struct pthread, member))); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%gs:%P1,%%eax\n\t" \ - "movl %%gs:%P2,%%edx" \ - : "=A" (__value) \ - : "i" (offsetof (struct pthread, member)), \ - "i" (offsetof (struct pthread, member) + 4)); \ - } \ - __value; }) + (*(__typeof (descr->member) __seg_gs *) \ + offsetof (struct pthread, member)); \ + }) -/* THREAD_GETMEM already forces a read. */ -#define THREAD_GETMEM_VOLATILE(descr, member) THREAD_GETMEM (descr, member) +#define THREAD_GETMEM_VOLATILE(descr, member) \ + ({ \ + _Static_assert (sizeof (descr->member) == 1 \ + || sizeof (descr->member) == 4 \ + || sizeof (descr->member) == 8, \ + "size of per-thread data"); \ + (*(volatile __typeof (descr->member) __seg_gs *) \ + offsetof (struct pthread, member)); \ + }) /* Same as THREAD_GETMEM, but the member offset can be non-constant. */ #define THREAD_GETMEM_NC(descr, member, idx) \ - ({ __typeof (descr->member[0]) __value; \ - _Static_assert (sizeof (__value) == 1 \ - || sizeof (__value) == 4 \ - || sizeof (__value) == 8, \ + ({ \ + _Static_assert (sizeof (descr->member[0]) == 1 \ + || sizeof (descr->member[0]) == 4 \ + || sizeof (descr->member[0]) == 8, \ "size of per-thread data"); \ - if (sizeof (__value) == 1) \ - asm volatile ("movb %%gs:%P2(%3),%b0" \ - : "=q" (__value) \ - : "0" (0), "i" (offsetof (struct pthread, member[0])), \ - "r" (idx)); \ - else if (sizeof (__value) == 4) \ - asm volatile ("movl %%gs:%P1(,%2,4),%0" \ - : "=r" (__value) \ - : "i" (offsetof (struct pthread, member[0])), \ - "r" (idx)); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%gs:%P1(,%2,8),%%eax\n\t" \ - "movl %%gs:4+%P1(,%2,8),%%edx" \ - : "=&A" (__value) \ - : "i" (offsetof (struct pthread, member[0])), \ - "r" (idx)); \ - } \ - __value; }) - - + (*(__typeof (descr->member[0]) __seg_gs *) \ + offsetof (struct pthread, member[idx])); \ + }) /* Set member of the thread descriptor directly. */ #define THREAD_SETMEM(descr, member, value) \ @@ -80,23 +55,9 @@ || sizeof (descr->member) == 4 \ || sizeof (descr->member) == 8, \ "size of per-thread data"); \ - if (sizeof (descr->member) == 1) \ - asm volatile ("movb %b0,%%gs:%P1" : \ - : "iq" (value), \ - "i" (offsetof (struct pthread, member))); \ - else if (sizeof (descr->member) == 4) \ - asm volatile ("movl %0,%%gs:%P1" : \ - : "ir" (value), \ - "i" (offsetof (struct pthread, member))); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%eax,%%gs:%P1\n\t" \ - "movl %%edx,%%gs:%P2" : \ - : "A" ((uint64_t) cast_to_integer (value)), \ - "i" (offsetof (struct pthread, member)), \ - "i" (offsetof (struct pthread, member) + 4)); \ - }}) - + (*(__typeof (descr->member) __seg_gs *) \ + offsetof (struct pthread, member) = (value)); \ + }) /* Same as THREAD_SETMEM, but the member offset can be non-constant. */ #define THREAD_SETMEM_NC(descr, member, idx, value) \ @@ -105,21 +66,6 @@ || sizeof (descr->member[0]) == 4 \ || sizeof (descr->member[0]) == 8, \ "size of per-thread data"); \ - if (sizeof (descr->member[0]) == 1) \ - asm volatile ("movb %b0,%%gs:%P1(%2)" : \ - : "iq" (value), \ - "i" (offsetof (struct pthread, member)), \ - "r" (idx)); \ - else if (sizeof (descr->member[0]) == 4) \ - asm volatile ("movl %0,%%gs:%P1(,%2,4)" : \ - : "ir" (value), \ - "i" (offsetof (struct pthread, member)), \ - "r" (idx)); \ - else /* 8 */ \ - { \ - asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t" \ - "movl %%edx,%%gs:4+%P1(,%2,8)" : \ - : "A" ((uint64_t) cast_to_integer (value)), \ - "i" (offsetof (struct pthread, member)), \ - "r" (idx)); \ - }}) + (*(__typeof (descr->member[0]) __seg_gs *) \ + offsetof (struct pthread, member[idx]) = (value)); \ + })