From e71e99c294058a61b7a8b9bb6da2f745ac51aa4f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 25 Mar 2009 14:30:04 -0400 Subject: x86, function-graph: only save return values on x86_64 Impact: speed up The return to handler portion of the function graph tracer should only need to save the return values. The caller already saved off the registers that the callee can modify. The returning function already saved the registers it modified. When we call our own trace function it too will save the registers that the callee must restore. There's no reason to save off anything more that the registers used to return the values. Note, I did a complete kernel build with this modification and the function graph tracer running on x86_64. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- arch/x86/kernel/entry_64.S | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) (limited to 'arch/x86/kernel/entry_64.S') diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index a331ec38af9..1ac99865591 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -147,27 +147,14 @@ END(ftrace_graph_caller) GLOBAL(return_to_handler) subq $80, %rsp + /* Save the return values */ movq %rax, (%rsp) - movq %rcx, 8(%rsp) - movq %rdx, 16(%rsp) - movq %rsi, 24(%rsp) - movq %rdi, 32(%rsp) - movq %r8, 40(%rsp) - movq %r9, 48(%rsp) - movq %r10, 56(%rsp) - movq %r11, 64(%rsp) + movq %rdx, 8(%rsp) call ftrace_return_to_handler movq %rax, 72(%rsp) - movq 64(%rsp), %r11 - movq 56(%rsp), %r10 - movq 48(%rsp), %r9 - movq 40(%rsp), %r8 - movq 32(%rsp), %rdi - movq 24(%rsp), %rsi - movq 16(%rsp), %rdx - movq 8(%rsp), %rcx + movq 8(%rsp), %rdx movq (%rsp), %rax addq $72, %rsp retq -- cgit v1.2.3 From 6cac5a924668a56c7ccefc345805f1fe0536a90e Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Sun, 29 Mar 2009 19:56:29 -0700 Subject: xen/x86-64: fix breakpoints and hardware watchpoints Native x86-64 uses the IST mechanism to run int3 and debug traps on an alternative stack. Xen does not do this, and so the frames were being misinterpreted by the ptrace code. This change special-cases these two exceptions by using Xen variants which run on the normal kernel stack properly. Impact: avoid crash or bad data when IST trap is invoked under Xen Signed-off-by: Jeremy Fitzhardinge --- arch/x86/include/asm/traps.h | 3 +++ arch/x86/kernel/entry_64.S | 5 +++++ arch/x86/xen/enlighten.c | 19 ++++++++++++++++++- 3 files changed, 26 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/entry_64.S') diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 0d5342515b8..c44e5002f2f 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -13,6 +13,9 @@ asmlinkage void divide_error(void); asmlinkage void debug(void); asmlinkage void nmi(void); asmlinkage void int3(void); +asmlinkage void xen_debug(void); +asmlinkage void xen_int3(void); +asmlinkage void xen_stack_segment(void); asmlinkage void overflow(void); asmlinkage void bounds(void); asmlinkage void invalid_op(void); diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 38946c6e843..bb01ce080b8 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1379,6 +1379,11 @@ END(xen_failsafe_callback) paranoidzeroentry_ist debug do_debug DEBUG_STACK paranoidzeroentry_ist int3 do_int3 DEBUG_STACK paranoiderrorentry stack_segment do_stack_segment +#ifdef CONFIG_XEN +zeroentry xen_debug do_debug +zeroentry xen_int3 do_int3 +errorentry xen_stack_segment do_stack_segment +#endif errorentry general_protection do_general_protection errorentry page_fault do_page_fault #ifdef CONFIG_X86_MCE diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 12a3159333b..7566e13c0ca 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -44,6 +45,7 @@ #include #include #include +#include #include #include #include @@ -428,11 +430,26 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, static int cvt_gate_to_trap(int vector, const gate_desc *val, struct trap_info *info) { + unsigned long addr; + if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) return 0; info->vector = vector; - info->address = gate_offset(*val); + + addr = gate_offset(*val); +#ifdef CONFIG_X86_64 + if (addr == (unsigned long)debug) + addr = (unsigned long)xen_debug; + else if (addr == (unsigned long)int3) + addr = (unsigned long)xen_int3; + else if (addr == (unsigned long)stack_segment) + addr = (unsigned long)xen_stack_segment; + else + WARN_ON(val->ist != 0); +#endif /* CONFIG_X86_64 */ + info->address = addr; + info->cs = gate_segment(*val); info->flags = val->dpl; /* interrupt gates clear IF */ -- cgit v1.2.3