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Kernel: Push missing IP and SP to mcontext in signal handler

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I was missing these two registers, messing up the whole siginfo_t
structure. This fixes libc's stack trace dump crashing :D
This commit is contained in:
Bananymous
2026-04-08 12:15:32 +03:00
parent a4ba1da65a
commit cd7d309fd1
2 changed files with 18 additions and 8 deletions
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13
kernel/arch/i686/Signal.S
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@@ -1,7 +1,7 @@
.section .userspace, "ax" .section .userspace, "ax"
// stack contains // stack contains
// (4 bytes) return address // (4 bytes) return address (on return stack)
// (4 bytes) return stack // (4 bytes) return stack
// (4 bytes) return rflags // (4 bytes) return rflags
// (8 bytes) restore sigmask // (8 bytes) restore sigmask
@@ -19,6 +19,10 @@ signal_trampoline:
pushl %eax pushl %eax
pushl %ebp pushl %ebp
movl 80(%esp), %eax
pushl %eax; addl $4, (%esp)
pushl (%eax)
// FIXME: populate these // FIXME: populate these
xorl %eax, %eax xorl %eax, %eax
pushl %eax // stack pushl %eax // stack
@@ -29,9 +33,9 @@ signal_trampoline:
pushl %eax // link pushl %eax // link
movl %esp, %edx // ucontext movl %esp, %edx // ucontext
leal 60(%esp), %esi // siginfo leal 68(%esp), %esi // siginfo
movl 56(%esp), %edi // signal number movl 64(%esp), %edi // signal number
movl 52(%esp), %eax // handlers movl 60(%esp), %eax // handlers
// align stack to 16 bytes // align stack to 16 bytes
movl %esp, %ebp movl %esp, %ebp
@@ -62,6 +66,7 @@ signal_trampoline:
int $0xF0 int $0xF0
// restore registers // restore registers
addl $8, %esp
popl %ebp popl %ebp
popl %eax popl %eax
popl %ebx popl %ebx

13
kernel/arch/x86_64/Signal.S
View File

@@ -1,7 +1,7 @@
.section .userspace, "ax" .section .userspace, "ax"
// stack contains // stack contains
// (8 bytes) return address // (8 bytes) return address (on return stack)
// (8 bytes) return stack // (8 bytes) return stack
// (8 bytes) return rflags // (8 bytes) return rflags
// (8 bytes) restore sigmask // (8 bytes) restore sigmask
@@ -27,6 +27,10 @@ signal_trampoline:
pushq %rax pushq %rax
pushq %rbp pushq %rbp
movq 208(%rsp), %rax
pushq %rax; addq $(128 + 8), (%rsp)
pushq (%rax)
// FIXME: populate these // FIXME: populate these
xorq %rax, %rax xorq %rax, %rax
pushq %rax // stack pushq %rax // stack
@@ -36,9 +40,9 @@ signal_trampoline:
pushq %rax // link pushq %rax // link
movq %rsp, %rdx // ucontext movq %rsp, %rdx // ucontext
leaq 176(%rsp), %rsi // siginfo leaq 192(%rsp), %rsi // siginfo
movq 168(%rsp), %rdi // signal number movq 184(%rsp), %rdi // signal number
movq 160(%rsp), %rax // handler movq 176(%rsp), %rax // handler
// align stack to 16 bytes // align stack to 16 bytes
movq %rsp, %rbp movq %rsp, %rbp
@@ -64,6 +68,7 @@ signal_trampoline:
syscall syscall
// restore registers // restore registers
addq $16, %rsp
popq %rbp popq %rbp
popq %rax popq %rax
popq %rbx popq %rbx