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kernel/x86_64: make sure stack is properly aligned in syscalls

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Just following the path of least resistance and adding andq $~15, %rsp
where appropriate. That should also make things harder to break
when changing the amount of stuff placed on stack before calling the
actual syscall routine.

Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
This commit is contained in:
Paweł Dziepak 2014-09-14 19:07:40 +02:00
parent f2f91078bd
commit acad7bf64a
1 changed files with 3 additions and 1 deletions
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4
src/system/kernel/arch/x86/64/interrupts.S
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@ -315,6 +315,7 @@ FUNCTION(x86_64_syscall_entry):
// Frame pointer is the iframe.
movq %rsp, %rbp
andq $~15, %rsp
// Preserve call number (R14 is callee-save), get thread pointer.
movq %rax, %r14
@ -367,10 +368,10 @@ FUNCTION(x86_64_syscall_entry):
// TODO: post-syscall tracing
.Lsyscall_return:
// Restore the original stack pointer and return.
movq %rbp, %rsp
.Lsyscall_return:
// Clear the restarted flag.
testl $THREAD_FLAGS_SYSCALL_RESTARTED, THREAD_flags(%r12)
jz 2f
@ -493,6 +494,7 @@ FUNCTION(x86_64_syscall_entry):
// Make space on the stack.
subq %rcx, %rsp
andq $~15, %rsp
movq %rsp, %rdi
// Set a fault handler.