From: David S. Miller Date: Mon, 25 Jul 2005 02:36:26 +0000 (-0700) Subject: [SPARC64]: Move syscall success and newchild state out of thread flags. X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=db7d9a4eb700be766cc9f29241483dbb1e748832;p=openwrt%2Fstaging%2Fblogic.git [SPARC64]: Move syscall success and newchild state out of thread flags. These two bits were accesses non-atomically from assembler code. So, in order to eliminate any potential races resulting from that, move these pieces of state into two bytes elsewhere in struct thread_info. Signed-off-by: David S. Miller --- diff --git a/arch/sparc64/kernel/entry.S b/arch/sparc64/kernel/entry.S index d781f10adc52..88332f00094a 100644 --- a/arch/sparc64/kernel/entry.S +++ b/arch/sparc64/kernel/entry.S @@ -1600,11 +1600,11 @@ sys_clone: flushw ba,pt %xcc, sparc_do_fork add %sp, PTREGS_OFF, %o2 ret_from_syscall: - /* Clear SPARC_FLAG_NEWCHILD, switch_to leaves thread.flags in - * %o7 for us. Check performance counter stuff too. + /* Clear current_thread_info()->new_child, and + * check performance counter stuff too. */ - andn %o7, _TIF_NEWCHILD, %l0 - stx %l0, [%g6 + TI_FLAGS] + stb %g0, [%g6 + TI_NEW_CHILD] + ldx [%g6 + TI_FLAGS], %l0 call schedule_tail mov %g7, %o0 andcc %l0, _TIF_PERFCTR, %g0 @@ -1720,12 +1720,11 @@ ret_sys_call: /* Check if force_successful_syscall_return() * was invoked. */ - ldx [%curptr + TI_FLAGS], %l0 - andcc %l0, _TIF_SYSCALL_SUCCESS, %g0 - be,pt %icc, 1f - andn %l0, _TIF_SYSCALL_SUCCESS, %l0 + ldub [%curptr + TI_SYS_NOERROR], %l0 + brz,pt %l0, 1f + nop ba,pt %xcc, 80f - stx %l0, [%curptr + TI_FLAGS] + stb %g0, [%curptr + TI_SYS_NOERROR] 1: cmp %o0, -ERESTART_RESTARTBLOCK diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c index a0cd2b2494d6..cffb1c8ab4fc 100644 --- a/arch/sparc64/kernel/process.c +++ b/arch/sparc64/kernel/process.c @@ -621,8 +621,8 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp, memcpy(child_trap_frame, (((struct sparc_stackf *)regs)-1), (TRACEREG_SZ+STACKFRAME_SZ)); t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) | (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) | - _TIF_NEWCHILD | (((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT); + t->new_child = 1; t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS; t->kregs = (struct pt_regs *)(child_trap_frame+sizeof(struct sparc_stackf)); t->fpsaved[0] = 0; diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c index 7e8e2919e186..b9b42491e118 100644 --- a/arch/sparc64/kernel/smp.c +++ b/arch/sparc64/kernel/smp.c @@ -137,7 +137,7 @@ void __init smp_callin(void) /* Clear this or we will die instantly when we * schedule back to this idler... */ - clear_thread_flag(TIF_NEWCHILD); + current_thread_info()->new_child = 0; /* Attach to the address space of init_task. */ atomic_inc(&init_mm.mm_count); diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c index a9f4596d7c2b..100b0107c4be 100644 --- a/arch/sparc64/kernel/traps.c +++ b/arch/sparc64/kernel/traps.c @@ -2125,6 +2125,8 @@ void __init trap_init(void) TI_PCR != offsetof(struct thread_info, pcr_reg) || TI_CEE_STUFF != offsetof(struct thread_info, cee_stuff) || TI_PRE_COUNT != offsetof(struct thread_info, preempt_count) || + TI_NEW_CHILD != offsetof(struct thread_info, new_child) || + TI_SYS_NOERROR != offsetof(struct thread_info, syscall_noerror) || TI_FPREGS != offsetof(struct thread_info, fpregs) || (TI_FPREGS & (64 - 1))) thread_info_offsets_are_bolixed_dave(); diff --git a/include/asm-sparc64/ptrace.h b/include/asm-sparc64/ptrace.h index 2d2b5a113d24..6194f771e9fc 100644 --- a/include/asm-sparc64/ptrace.h +++ b/include/asm-sparc64/ptrace.h @@ -94,8 +94,9 @@ struct sparc_trapf { #define STACKFRAME32_SZ sizeof(struct sparc_stackf32) #ifdef __KERNEL__ -#define force_successful_syscall_return() \ - set_thread_flag(TIF_SYSCALL_SUCCESS) +#define force_successful_syscall_return() \ +do { current_thread_info()->syscall_noerror = 1; \ +} while (0) #define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV)) #define instruction_pointer(regs) ((regs)->tpc) #ifdef CONFIG_SMP diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h index f9be2c5b4dc9..ee4bdfc6b88f 100644 --- a/include/asm-sparc64/system.h +++ b/include/asm-sparc64/system.h @@ -190,24 +190,23 @@ do { if (test_thread_flag(TIF_PERFCTR)) { \ "wrpr %%g1, %%cwp\n\t" \ "ldx [%%g6 + %3], %%o6\n\t" \ "ldub [%%g6 + %2], %%o5\n\t" \ - "ldx [%%g6 + %4], %%o7\n\t" \ + "ldub [%%g6 + %4], %%o7\n\t" \ "mov %%g6, %%l2\n\t" \ "wrpr %%o5, 0x0, %%wstate\n\t" \ "ldx [%%sp + 2047 + 0x70], %%i6\n\t" \ "ldx [%%sp + 2047 + 0x78], %%i7\n\t" \ "wrpr %%g0, 0x94, %%pstate\n\t" \ "mov %%l2, %%g6\n\t" \ - "ldx [%%g6 + %7], %%g4\n\t" \ + "ldx [%%g6 + %6], %%g4\n\t" \ "wrpr %%g0, 0x96, %%pstate\n\t" \ - "andcc %%o7, %6, %%g0\n\t" \ - "beq,pt %%icc, 1f\n\t" \ + "brz,pt %%o7, 1f\n\t" \ " mov %%g7, %0\n\t" \ "b,a ret_from_syscall\n\t" \ "1:\n\t" \ : "=&r" (last) \ : "0" (next->thread_info), \ - "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_FLAGS), "i" (TI_CWP), \ - "i" (_TIF_NEWCHILD), "i" (TI_TASK) \ + "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_NEW_CHILD), \ + "i" (TI_CWP), "i" (TI_TASK) \ : "cc", \ "g1", "g2", "g3", "g7", \ "l2", "l3", "l4", "l5", "l6", "l7", \ diff --git a/include/asm-sparc64/thread_info.h b/include/asm-sparc64/thread_info.h index a1d25c06f92a..352d9943661a 100644 --- a/include/asm-sparc64/thread_info.h +++ b/include/asm-sparc64/thread_info.h @@ -47,7 +47,9 @@ struct thread_info { struct pt_regs *kregs; struct exec_domain *exec_domain; int preempt_count; /* 0 => preemptable, <0 => BUG */ - int __pad; + __u8 new_child; + __u8 syscall_noerror; + __u16 __pad; unsigned long *utraps; @@ -87,6 +89,8 @@ struct thread_info { #define TI_KREGS 0x00000028 #define TI_EXEC_DOMAIN 0x00000030 #define TI_PRE_COUNT 0x00000038 +#define TI_NEW_CHILD 0x0000003c +#define TI_SYS_NOERROR 0x0000003d #define TI_UTRAPS 0x00000040 #define TI_REG_WINDOW 0x00000048 #define TI_RWIN_SPTRS 0x000003c8 @@ -219,10 +223,10 @@ register struct thread_info *current_thread_info_reg asm("g6"); #define TIF_UNALIGNED 5 /* allowed to do unaligned accesses */ #define TIF_NEWSIGNALS 6 /* wants new-style signals */ #define TIF_32BIT 7 /* 32-bit binary */ -#define TIF_NEWCHILD 8 /* just-spawned child process */ +/* flag bit 8 is available */ #define TIF_SECCOMP 9 /* secure computing */ #define TIF_SYSCALL_AUDIT 10 /* syscall auditing active */ -#define TIF_SYSCALL_SUCCESS 11 +/* flag bit 11 is available */ /* NOTE: Thread flags >= 12 should be ones we have no interest * in using in assembly, else we can't use the mask as * an immediate value in instructions such as andcc. @@ -239,10 +243,8 @@ register struct thread_info *current_thread_info_reg asm("g6"); #define _TIF_UNALIGNED (1<