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native,cte: refactor the code constructing context in signal handler 

* it is safer to use C type
This commit is contained in:
Zihao Yu 2020-02-08 17:02:13 +08:00
parent d49f9f61bf
commit da842bd755
2 changed files with 10 additions and 16 deletions
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23
am/src/native/cte.c
View File

@ -38,8 +38,8 @@ void __am_irq_handle(_Context *c) {
setcontext(&c->uc);
}
static void setup_stack(uintptr_t event, ucontext_t *c) {
void *rip = (void *)c->uc_mcontext.gregs[REG_RIP];
static void setup_stack(uintptr_t event, ucontext_t *uc) {
void *rip = (void *)uc->uc_mcontext.gregs[REG_RIP];
extern uint8_t _start, _etext;
int signal_safe = IN_RANGE(rip, RANGE(&_start, &_etext)) || __am_in_userspace(rip) ||
// Hack here: "+13" points to the instruction after syscall. This is the
@ -61,21 +61,18 @@ static void setup_stack(uintptr_t event, ucontext_t *c) {
if (event == _EVENT_SYSCALL) { rip += SYSCALL_INSTR_LEN; }
else if (event == _EVENT_YIELD) { rip += YIELD_INSTR_LEN; }
// skip the red zone of the stack frame, see the amd64 ABI manual for details
uintptr_t rsp = c->uc_mcontext.gregs[REG_RSP] - RED_NONE_SIZE;
#define PUSH(x) rsp -= sizeof(uintptr_t); *(uintptr_t *)rsp = (uintptr_t)(x)
PUSH(rip);
_Context *c = (_Context *)uc->uc_mcontext.gregs[REG_RSP] - 1;
c->rip = (uintptr_t)rip;
// rflags is not preserved by getcontext(), save it here
PUSH(c->uc_mcontext.gregs[REG_EFL]);
uintptr_t sti = __am_is_sigmask_sti(&c->uc_sigmask);
PUSH(sti);
c->rflags = uc->uc_mcontext.gregs[REG_EFL];
c->sti = __am_is_sigmask_sti(&uc->uc_sigmask);
// disable interrupt
__am_get_intr_sigmask(&c->uc_sigmask);
__am_get_intr_sigmask(&uc->uc_sigmask);
c->uc_mcontext.gregs[REG_RSP] = rsp;
c->uc_mcontext.gregs[REG_RIP] = (uintptr_t)__am_asm_trap;
// construct the remaining part of the context at trap.S
uc->uc_mcontext.gregs[REG_RSP] = (uintptr_t)&c->sti;
uc->uc_mcontext.gregs[REG_RIP] = (uintptr_t)__am_asm_trap;
}
static void sig_handler(int sig, siginfo_t *info, void *ucontext) {

3
am/src/native/platform.h
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@ -7,9 +7,6 @@
#include <klib.h>
#include <klib-macros.h>
// the size of red zone of the stack frame, see the amd64 ABI manual for details
#define RED_NONE_SIZE 128
void __am_get_example_uc(_Context *r);
void __am_get_intr_sigmask(sigset_t *s);
int __am_is_sigmask_sti(sigset_t *s);