From d7161a65341556bacb5e6654e133803f46f51063 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 26 Sep 2008 10:36:41 -0500 Subject: kgdb, x86, arm, mips, powerpc: ignore user space single stepping On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel --- arch/arm/kernel/kgdb.c | 2 -- arch/mips/kernel/kgdb.c | 3 +-- arch/powerpc/kernel/kgdb.c | 5 ++--- arch/x86/kernel/kgdb.c | 18 +++++++++++------- 4 files changed, 14 insertions(+), 14 deletions(-) (limited to 'arch') diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c index aaffaecffcd1..ba8ccfede964 100644 --- a/arch/arm/kernel/kgdb.c +++ b/arch/arm/kernel/kgdb.c @@ -111,8 +111,6 @@ int kgdb_arch_handle_exception(int exception_vector, int signo, case 'D': case 'k': case 'c': - kgdb_contthread = NULL; - /* * Try to read optional parameter, pc unchanged if no parm. * If this was a compiled breakpoint, we need to move diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c index 8f6d58ede33c..6e152c80cd4a 100644 --- a/arch/mips/kernel/kgdb.c +++ b/arch/mips/kernel/kgdb.c @@ -236,8 +236,7 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code, atomic_set(&kgdb_cpu_doing_single_step, -1); if (remcom_in_buffer[0] == 's') - if (kgdb_contthread) - atomic_set(&kgdb_cpu_doing_single_step, cpu); + atomic_set(&kgdb_cpu_doing_single_step, cpu); return 0; } diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index b4fdf2f2743c..fe8f71dd0b3f 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -347,9 +347,8 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code, linux_regs->msr |= MSR_SE; #endif kgdb_single_step = 1; - if (kgdb_contthread) - atomic_set(&kgdb_cpu_doing_single_step, - raw_smp_processor_id()); + atomic_set(&kgdb_cpu_doing_single_step, + raw_smp_processor_id()); } return 0; } diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index f47f0eb886b8..00f7896c9a19 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -378,10 +378,8 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, if (remcomInBuffer[0] == 's') { linux_regs->flags |= X86_EFLAGS_TF; kgdb_single_step = 1; - if (kgdb_contthread) { - atomic_set(&kgdb_cpu_doing_single_step, - raw_smp_processor_id()); - } + atomic_set(&kgdb_cpu_doing_single_step, + raw_smp_processor_id()); } get_debugreg(dr6, 6); @@ -466,9 +464,15 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) case DIE_DEBUG: if (atomic_read(&kgdb_cpu_doing_single_step) == - raw_smp_processor_id() && - user_mode(regs)) - return single_step_cont(regs, args); + raw_smp_processor_id()) { + if (user_mode(regs)) + return single_step_cont(regs, args); + break; + } else if (test_thread_flag(TIF_SINGLESTEP)) + /* This means a user thread is single stepping + * a system call which should be ignored + */ + return NOTIFY_DONE; /* fall through */ default: if (user_mode(regs)) -- cgit v1.2.3 From 703a1edcd1534468fc18f733c03bd91a65c8c6f0 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 26 Sep 2008 10:36:42 -0500 Subject: kgdb, x86_64: fix PS CS SS registers in gdb serial On x86_64 the gdb serial register structure defines the PS (also known as eflags), CS and SS registers as 4 bytes entities. This patch splits the x86_64 regnames enum into a 32 and 64 version to account for the 32 bit entities in the gdb serial packets. Also the program counter is properly filled in for the sleeping threads. Signed-off-by: Jason Wessel --- arch/x86/kernel/kgdb.c | 25 +++++++++++++++++++++---- include/asm-x86/kgdb.h | 20 +++++++++----------- 2 files changed, 30 insertions(+), 15 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 00f7896c9a19..8282a2139681 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -69,6 +69,9 @@ static int gdb_x86vector = -1; */ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) { +#ifndef CONFIG_X86_32 + u32 *gdb_regs32 = (u32 *)gdb_regs; +#endif gdb_regs[GDB_AX] = regs->ax; gdb_regs[GDB_BX] = regs->bx; gdb_regs[GDB_CX] = regs->cx; @@ -76,9 +79,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) gdb_regs[GDB_SI] = regs->si; gdb_regs[GDB_DI] = regs->di; gdb_regs[GDB_BP] = regs->bp; - gdb_regs[GDB_PS] = regs->flags; gdb_regs[GDB_PC] = regs->ip; #ifdef CONFIG_X86_32 + gdb_regs[GDB_PS] = regs->flags; gdb_regs[GDB_DS] = regs->ds; gdb_regs[GDB_ES] = regs->es; gdb_regs[GDB_CS] = regs->cs; @@ -94,6 +97,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) gdb_regs[GDB_R13] = regs->r13; gdb_regs[GDB_R14] = regs->r14; gdb_regs[GDB_R15] = regs->r15; + gdb_regs32[GDB_PS] = regs->flags; + gdb_regs32[GDB_CS] = regs->cs; + gdb_regs32[GDB_SS] = regs->ss; #endif gdb_regs[GDB_SP] = regs->sp; } @@ -112,6 +118,9 @@ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) */ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) { +#ifndef CONFIG_X86_32 + u32 *gdb_regs32 = (u32 *)gdb_regs; +#endif gdb_regs[GDB_AX] = 0; gdb_regs[GDB_BX] = 0; gdb_regs[GDB_CX] = 0; @@ -129,8 +138,10 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) gdb_regs[GDB_FS] = 0xFFFF; gdb_regs[GDB_GS] = 0xFFFF; #else - gdb_regs[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); - gdb_regs[GDB_PC] = 0; + gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); + gdb_regs32[GDB_CS] = __KERNEL_CS; + gdb_regs32[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_PC] = p->thread.ip; gdb_regs[GDB_R8] = 0; gdb_regs[GDB_R9] = 0; gdb_regs[GDB_R10] = 0; @@ -153,6 +164,9 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) */ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) { +#ifndef CONFIG_X86_32 + u32 *gdb_regs32 = (u32 *)gdb_regs; +#endif regs->ax = gdb_regs[GDB_AX]; regs->bx = gdb_regs[GDB_BX]; regs->cx = gdb_regs[GDB_CX]; @@ -160,9 +174,9 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) regs->si = gdb_regs[GDB_SI]; regs->di = gdb_regs[GDB_DI]; regs->bp = gdb_regs[GDB_BP]; - regs->flags = gdb_regs[GDB_PS]; regs->ip = gdb_regs[GDB_PC]; #ifdef CONFIG_X86_32 + regs->flags = gdb_regs[GDB_PS]; regs->ds = gdb_regs[GDB_DS]; regs->es = gdb_regs[GDB_ES]; regs->cs = gdb_regs[GDB_CS]; @@ -175,6 +189,9 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) regs->r13 = gdb_regs[GDB_R13]; regs->r14 = gdb_regs[GDB_R14]; regs->r15 = gdb_regs[GDB_R15]; + regs->flags = gdb_regs32[GDB_PS]; + regs->cs = gdb_regs32[GDB_CS]; + regs->ss = gdb_regs32[GDB_SS]; #endif } diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h index e86b3060bdcb..94d63db10365 100644 --- a/include/asm-x86/kgdb.h +++ b/include/asm-x86/kgdb.h @@ -39,8 +39,9 @@ enum regnames { GDB_FS, /* 14 */ GDB_GS, /* 15 */ }; +#define NUMREGBYTES ((GDB_GS+1)*4) #else /* ! CONFIG_X86_32 */ -enum regnames { +enum regnames64 { GDB_AX, /* 0 */ GDB_BX, /* 1 */ GDB_CX, /* 2 */ @@ -58,18 +59,15 @@ enum regnames { GDB_R14, /* 14 */ GDB_R15, /* 15 */ GDB_PC, /* 16 */ - GDB_PS, /* 17 */ }; -#endif /* CONFIG_X86_32 */ -/* - * Number of bytes of registers: - */ -#ifdef CONFIG_X86_32 -# define NUMREGBYTES 64 -#else -# define NUMREGBYTES ((GDB_PS+1)*8) -#endif +enum regnames32 { + GDB_PS = 34, + GDB_CS, + GDB_SS, +}; +#define NUMREGBYTES ((GDB_SS+1)*4) +#endif /* CONFIG_X86_32 */ static inline void arch_kgdb_breakpoint(void) { -- cgit v1.2.3