X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=include%2Fust%2Fprocessor.h;h=95e1164af5ad2085527ddaf8d4579c0708fb8bf7;hb=9692fa182535c55f0a03f79f26211aed9906da82;hp=2546cbfd88690f15d3b92cb93b52f7ce78a87cde;hpb=7756d65ab75135fc9b62b5376fd43f3fb1d534cc;p=ust.git diff --git a/include/ust/processor.h b/include/ust/processor.h index 2546cbf..95e1164 100644 --- a/include/ust/processor.h +++ b/include/ust/processor.h @@ -15,8 +15,8 @@ struct registers { long esi; long ebp; long edx; - long ecx; long edi; + long ecx; long ebx; long eax; long eflags; @@ -25,7 +25,27 @@ struct registers { #ifdef CONFIG_UST_GDB_INTEGRATION -//#error "GDB integration not supported for x86-32 yet." +/* save_registers - saves most of the processor's registers so + * they are available to the probe. gdb uses this to give the + * value of local variables. + * + * Saving all registers without losing any of their values is + * tricky. + * + * We cannot pass to the asm stub the address of a registers structure + * on the stack, because it will use a register and override its value. + * + * We don't want to use a stub to push the regs on the stack and then + * another stub to copy them to a structure because changing %sp in asm + * and then returning to C (even briefly) can have unexpected results. + * Also, gcc might modify %sp between the stubs in reaction to the + * register needs of the second stub that needs to know where to copy + * the register values. + * + * So the chosen approach is to use another stack, declared in thread- + * local storage, to push the registers. They are subsequently copied + * to the stack, by C code. + */ #define save_registers(regsptr) \ asm volatile ( \ @@ -35,46 +55,80 @@ struct registers { "pushfl\n\t" \ /* eax will hold the ptr to the private stack bottom */ \ "pushl %%eax\n\t" \ - /* ebx will be used to temporarily hold the stack bottom addr */ \ + /* ebx is used for TLS access */ \ "pushl %%ebx\n\t" \ - /* rdi is the input to __tls_get_addr, and also a temp var */ \ - "pushl %%edi\n\t" \ + /* ecx will be used to temporarily hold the stack bottom addr */\ + "pushl %%ecx\n\t" \ + /* rdi is the input to __tls_get_addr, and also a temp var */ \ + "pushl %%edi\n\t" \ + /* For TLS access, we have to do function calls. However, \ + * we must not lose the original value of: \ + * esp, eflags, eax, ebx, ecx, edx, esi, edi, ebp, cs, ss \ + * \ + * Some registers' original values have already been saved: \ + * esp, eflags, eax, ebx, ecx, edi \ + * \ + * In addition, the i386 ABI says the following registers belong\ + * to the caller function: \ + * esp, ebp, esi, edi, ebx \ + * \ + * The following registers should not be changed by the callee: \ + * cs, ss \ + * \ + * Therefore, the following registers must be explicitly \ + * preserved: \ + * edx \ + */ \ + "pushl %%edx\n\t" \ + /* Get GOT address */ \ + "call __i686.get_pc_thunk.bx\n\t" \ + "addl $_GLOBAL_OFFSET_TABLE_, %%ebx\n\t" \ /* Start TLS access of private reg stack pointer */ \ "leal ust_reg_stack_ptr@tlsgd(,%%ebx,1),%%eax\n\t" \ "call ___tls_get_addr@plt\n\t" \ /* --- End TLS access */ \ /* check if ust_reg_stack_ptr has been initialized */ \ - "movl (%%eax),%%ebx\n\t" \ - "testl %%ebx,%%ebx\n\t" \ + "movl (%%eax),%%ecx\n\t" \ + "testl %%ecx,%%ecx\n\t" \ "jne 1f\n\t" \ - "movl %%eax,%%ebx\n\t" \ + "movl %%eax,%%ecx\n\t" \ + /* Save ecx because we are using it. */ \ + "pushl %%ecx\n\t" \ /* Start TLS access of private reg stack */ \ "leal ust_reg_stack@tlsgd(,%%ebx,1),%%eax\n\t" \ "call ___tls_get_addr@plt\n\t" \ /* --- End TLS access */ \ + "popl %%ecx\n\t" \ "addl $500,%%eax\n\t" \ - "movl %%eax,(%%ebx)\n\t" \ - "movl %%ebx,%%eax\n\t" \ + "movl %%eax,(%%ecx)\n\t" \ + "movl %%ecx,%%eax\n\t" \ /* now the pointer to the private stack is in eax. \ must add stack size so the ptr points to the stack bottom. */ \ "1:\n\t" \ + /* edx was pushed for function calls */ \ + "popl %%edx\n\t" \ /* Manually push esp to private stack */ \ "addl $-4,(%%eax)\n\t" \ - "movl 16(%%esp), %%edi\n\t" \ + "movl 20(%%esp), %%edi\n\t" \ "movl (%%eax), %%ebx\n\t" \ "movl %%edi, (%%ebx)\n\t" \ /* Manually push eflags to private stack */ \ "addl $-4,(%%eax)\n\t" \ - "movl 12(%%esp), %%edi\n\t" \ + "movl 16(%%esp), %%edi\n\t" \ "movl (%%eax), %%ebx\n\t" \ "movl %%edi, (%%ebx)\n\t" \ /* Manually push eax to private stack */ \ "addl $-4,(%%eax)\n\t" \ - "movl 8(%%esp), %%edi\n\t" \ + "movl 12(%%esp), %%edi\n\t" \ "movl (%%eax), %%ebx\n\t" \ "movl %%edi, (%%ebx)\n\t" \ /* Manually push ebx to private stack */ \ "addl $-4,(%%eax)\n\t" \ + "movl 8(%%esp), %%edi\n\t" \ + "movl (%%eax), %%ebx\n\t" \ + "movl %%edi, (%%ebx)\n\t" \ + /* Manually push ecx to private stack */ \ + "addl $-4,(%%eax)\n\t" \ "movl 4(%%esp), %%edi\n\t" \ "movl (%%eax), %%ebx\n\t" \ "movl %%edi, (%%ebx)\n\t" \ @@ -87,12 +141,10 @@ struct registers { /* -- esp already pushed -- */ \ /* -- eax already pushed -- */ \ /* -- ebx already pushed -- */ \ + /* -- ecx already pushed -- */ \ /* -- edi already pushed -- */ \ "addl $-4,(%%eax)\n\t" \ "movl (%%eax), %%ebx\n\t" \ - "movl %%ecx,(%%ebx)\n\t" \ - "addl $-4,(%%eax)\n\t" \ - "movl (%%eax), %%ebx\n\t" \ "movl %%edx,(%%ebx)\n\t" \ "addl $-4,(%%eax)\n\t" \ "movl (%%eax), %%ebx\n\t" \ @@ -110,6 +162,7 @@ struct registers { "movw %%ss, (%%ebx)\n\t" \ /* restore original values of regs that were used internally */ \ "popl %%edi\n\t" \ + "popl %%ecx\n\t" \ "popl %%ebx\n\t" \ "popl %%eax\n\t" \ /* cancel push of rsp */ \ @@ -120,18 +173,16 @@ struct registers { memcpy(regsptr, (void *)ust_reg_stack_ptr, sizeof(struct registers)); \ ust_reg_stack_ptr = (void *)(((long)ust_reg_stack_ptr) + sizeof(struct registers)); -#define save_ip(channel,name) - - #else /* CONFIG_UST_GDB_INTEGRATION */ -#define save_ip(channel,name) #define save_registers(a) #endif /* CONFIG_UST_GDB_INTEGRATION */ #define RELATIVE_ADDRESS(__rel_label__) __rel_label__ +#define ARCH_COPY_ADDR(src, dst) "lea " src "," dst + #define _ASM_PTR ".long " #else /* below is code for x86-64 */ @@ -160,12 +211,6 @@ struct registers { }; #ifdef CONFIG_UST_GDB_INTEGRATION -#define save_ip(channel,name) \ - asm (".section __marker_addr,\"aw\",@progbits\n\t" \ - _ASM_PTR "%c[marker_struct], (1f)\n\t" \ - ".previous\n\t" \ - "1:\n\t" \ - :: [marker_struct] "i" (&__mark_##channel##_##name));\ #define save_registers(regsptr) \ asm volatile ( \ @@ -179,6 +224,32 @@ struct registers { "pushq %%rbx\n\t" \ /* rdi is the input to __tls_get_addr, and also a temp var */ \ "pushq %%rdi\n\t" \ + /* For TLS access, we have to do function calls. However, \ + * we must not lose the original value of: \ + * rsp, rflags, rax, rbx, rcx, rdx, rsi, rdi, rbp, r8, r9 \ + * r10, r11, r12, r13, r14, r15, cs, ss \ + * \ + * Some registers' original values have already been saved: \ + * rsp, rflags, rax, rbx, rdi \ + * \ + * In addition, the x86-64 ABI says the following registers \ + * belong to the caller function: \ + * rbp, rbx, r12, r13, r14, r15 \ + * \ + * The following registers should not be changed by the callee: \ + * cs, ss \ + * \ + * Therefore, the following registers must be explicitly \ + * preserved: \ + * rcx, rdx, rsi, r8, r9, r10, r11 \ + */ \ + "pushq %%rcx\n\t" \ + "pushq %%rdx\n\t" \ + "pushq %%rsi\n\t" \ + "pushq %%r8\n\t" \ + "pushq %%r9\n\t" \ + "pushq %%r10\n\t" \ + "pushq %%r11\n\t" \ /* Start TLS access of private reg stack pointer */ \ ".byte 0x66\n\t" \ "leaq ust_reg_stack_ptr@tlsgd(%%rip), %%rdi\n\t" \ @@ -204,6 +275,14 @@ struct registers { /* now the pointer to the private stack is in rax. must add stack size so the ptr points to the stack bottom. */ \ "1:\n\t" \ + /* Pop regs that were pushed for function calls */ \ + "popq %%r11\n\t" \ + "popq %%r10\n\t" \ + "popq %%r9\n\t" \ + "popq %%r8\n\t" \ + "popq %%rsi\n\t" \ + "popq %%rdx\n\t" \ + "popq %%rcx\n\t" \ /* Manually push rsp to private stack */ \ "addq $-8,(%%rax)\n\t" \ "movq 32(%%rsp), %%rdi\n\t" \ @@ -294,7 +373,6 @@ struct registers { #else /* CONFIG_UST_GDB_INTEGRATION */ -#define save_ip(channel,name) #define save_registers(a) #endif /* CONFIG_UST_GDB_INTEGRATION */ @@ -303,6 +381,8 @@ struct registers { * in a relocatable way. On x86-64, this uses a special (%rip) notation. */ #define RELATIVE_ADDRESS(__rel_label__) __rel_label__(%%rip) +#define ARCH_COPY_ADDR(src, dst) "lea " src "(%%rip)," dst + #define _ASM_PTR ".quad " #endif