From 1f31243a8c80fac27e52cc362cb1e2c922cf0e1b Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 31 Jul 2024 16:44:12 +0200 Subject: [PATCH] bsd-user/x86_64/target_arch_thread.h: Align stack bsd-user qemu-x86_64 almost immediately dies with: qemu: 0x4002201a68: unhandled CPU exception 0xd - aborting on FreeBSD 14.1-RELEASE. This is an instruction that requires alignment: (gdb) x/i 0x4002201a68 0x4002201a68: movaps %xmm0,-0x40(%rbp) and the argument is not aligned: (gdb) p/x env->regs[5] $1 = 0x822443b58 A quick experiment shows that the userspace entry point expects misaligned rsp: (gdb) starti (gdb) p/x $rsp $1 = 0x7fffffffeaa8 Emulate this behavior in bsd-user. [[ applied Richard's suggestion ]] Signed-off-by: Ilya Leoshkevich Reviewed-by: Richard Henderson Reviewed-by: Warner Losh Signed-off-by: Warner Losh --- bsd-user/x86_64/target_arch_thread.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/bsd-user/x86_64/target_arch_thread.h b/bsd-user/x86_64/target_arch_thread.h index 52c28906d6..7739bb2154 100644 --- a/bsd-user/x86_64/target_arch_thread.h +++ b/bsd-user/x86_64/target_arch_thread.h @@ -31,7 +31,7 @@ static inline void target_thread_init(struct target_pt_regs *regs, struct image_info *infop) { regs->rax = 0; - regs->rsp = infop->start_stack; + regs->rsp = ((infop->start_stack - 8) & ~0xfUL) + 8; regs->rip = infop->entry; regs->rdi = infop->start_stack; }