| From 239d553dba29521cde2f882912f949c815306ab6 Mon Sep 17 00:00:00 2001 |
| From: Stephen Barber <smbarber@chromium.org> |
| Date: Wed, 8 Apr 2020 19:50:34 -0700 |
| Subject: [PATCH 2/2] amd64: replace array with inline asm |
| |
| Submitted upstream as https://github.com/canonical/libco/pull/13 |
| |
| --- |
| amd64.c | 93 ++++++++++++++++++++++++++------------------------------- |
| 1 file changed, 43 insertions(+), 50 deletions(-) |
| |
| diff --git a/amd64.c b/amd64.c |
| index ab62bd9..0a93e30 100755 |
| --- a/amd64.c |
| +++ b/amd64.c |
| @@ -13,12 +13,12 @@ static thread_local long long co_active_buffer[64]; |
| static thread_local cothread_t co_active_handle = 0; |
| static void (*co_swap)(cothread_t, cothread_t) = 0; |
| |
| +#ifdef _WIN32 |
| #ifdef LIBCO_MPROTECT |
| alignas(4096) |
| #else |
| section(text) |
| #endif |
| -#ifdef _WIN32 |
| /* ABI: Win64 */ |
| static const unsigned char co_swap_function[4096] = { |
| 0x48, 0x89, 0x22, /* mov [rdx],rsp */ |
| @@ -78,37 +78,39 @@ static void (*co_swap)(cothread_t, cothread_t) = 0; |
| #endif |
| } |
| #else |
| - /* ABI: SystemV */ |
| - static const unsigned char co_swap_function[4096] = { |
| - 0x48, 0x89, 0x26, /* mov [rsi],rsp */ |
| - 0x48, 0x8b, 0x27, /* mov rsp,[rdi] */ |
| - 0x58, /* pop rax */ |
| - 0x48, 0x89, 0x6e, 0x08, /* mov [rsi+ 8],rbp */ |
| - 0x48, 0x89, 0x5e, 0x10, /* mov [rsi+16],rbx */ |
| - 0x4c, 0x89, 0x66, 0x18, /* mov [rsi+24],r12 */ |
| - 0x4c, 0x89, 0x6e, 0x20, /* mov [rsi+32],r13 */ |
| - 0x4c, 0x89, 0x76, 0x28, /* mov [rsi+40],r14 */ |
| - 0x4c, 0x89, 0x7e, 0x30, /* mov [rsi+48],r15 */ |
| - 0x48, 0x8b, 0x6f, 0x08, /* mov rbp,[rdi+ 8] */ |
| - 0x48, 0x8b, 0x5f, 0x10, /* mov rbx,[rdi+16] */ |
| - 0x4c, 0x8b, 0x67, 0x18, /* mov r12,[rdi+24] */ |
| - 0x4c, 0x8b, 0x6f, 0x20, /* mov r13,[rdi+32] */ |
| - 0x4c, 0x8b, 0x77, 0x28, /* mov r14,[rdi+40] */ |
| - 0x4c, 0x8b, 0x7f, 0x30, /* mov r15,[rdi+48] */ |
| - 0xff, 0xe0, /* jmp rax */ |
| - }; |
| |
| + void co_swap_function(cothread_t, cothread_t); |
| + |
| + __asm__( |
| + ".text\n" |
| + ".align 4\n" |
| + ".type co_swap_function @function\n" |
| + ".intel_syntax noprefix\n" |
| + "co_swap_function:\n" |
| + |
| + "mov [rsi],rsp\n" |
| + "mov rsp,[rdi]\n" |
| + "pop rax\n" |
| + "mov [rsi+ 8],rbp\n" |
| + "mov [rsi+16],rbx\n" |
| + "mov [rsi+24],r12\n" |
| + "mov [rsi+32],r13\n" |
| + "mov [rsi+40],r14\n" |
| + "mov [rsi+48],r15\n" |
| + "mov rbp,[rdi+ 8]\n" |
| + "mov rbx,[rdi+16]\n" |
| + "mov r12,[rdi+24]\n" |
| + "mov r13,[rdi+32]\n" |
| + "mov r14,[rdi+40]\n" |
| + "mov r15,[rdi+48]\n" |
| + "jmp rax\n" |
| + |
| + ".size co_swap_function, .-co_swap_function\n" |
| + ".att_syntax\n" |
| + ); |
| #include <unistd.h> |
| - #include <sys/mman.h> |
| |
| - static void co_init() { |
| - #ifdef LIBCO_MPROTECT |
| - unsigned long long addr = (unsigned long long)co_swap_function; |
| - unsigned long long base = addr - (addr % sysconf(_SC_PAGESIZE)); |
| - unsigned long long size = (addr - base) + sizeof co_swap_function; |
| - mprotect((void*)base, size, PROT_READ | PROT_EXEC); |
| - #endif |
| - } |
| + static void co_init() {} |
| #endif |
| |
| static void crash() { |
| @@ -129,33 +131,20 @@ cothread_t co_derive(void* memory, unsigned int size, void (*entrypoint)(void)) |
| if(!co_active_handle) co_active_handle = &co_active_buffer; |
| |
| if(handle = (cothread_t)memory) { |
| - long long *p = (long long*)((char*)handle + size); /* seek to top of stack */ |
| - *--p = (long long)crash; /* crash if entrypoint returns */ |
| - *--p = (long long)entrypoint; /* start of function */ |
| - *(long long*)handle = (long long)p; /* stack pointer */ |
| + unsigned int offset = (size & ~15) - 32; |
| + long long *p = (long long*)((char*)handle + offset); /* seek to top of stack */ |
| + *--p = (long long)crash; /* crash if entrypoint returns */ |
| + *--p = (long long)entrypoint; /* start of function */ |
| + *(long long*)handle = (long long)p; /* stack pointer */ |
| } |
| |
| return handle; |
| } |
| |
| cothread_t co_create(unsigned int size, void (*entrypoint)(void)) { |
| - cothread_t handle; |
| - if(!co_swap) { |
| - co_init(); |
| - co_swap = (void (*)(cothread_t, cothread_t))co_swap_function; |
| - } |
| - if(!co_active_handle) co_active_handle = &co_active_buffer; |
| - size += 512; /* allocate additional space for storage */ |
| - size &= ~15; /* align stack to 16-byte boundary */ |
| - |
| - if(handle = (cothread_t)malloc(size)) { |
| - long long *p = (long long*)((char*)handle + size); /* seek to top of stack */ |
| - *--p = (long long)crash; /* crash if entrypoint returns */ |
| - *--p = (long long)entrypoint; /* start of function */ |
| - *(long long*)handle = (long long)p; /* stack pointer */ |
| - } |
| - |
| - return handle; |
| + void* memory = malloc(size); |
| + if(!memory) return (cothread_t)0; |
| + return co_derive(memory, size, entrypoint); |
| } |
| |
| void co_delete(cothread_t handle) { |
| @@ -167,6 +156,10 @@ void co_switch(cothread_t handle) { |
| co_swap(co_active_handle = handle, co_previous_handle); |
| } |
| |
| +int co_serializable() { |
| + return 1; |
| +} |
| + |
| #ifdef __cplusplus |
| } |
| #endif |
| -- |
| 2.26.0.292.g33ef6b2f38-goog |
| |
