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Re: [Qemu-devel] [PATCH] linux-user: provide frame information in x86-64
Re: [Qemu-devel] [PATCH] linux-user: provide frame information in x86-64 safe_syscall
Fri, 27 May 2016 09:21:01 -0700
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0
On 05/27/2016 08:06 AM, Peter Maydell wrote:
@@ -31,6 +32,8 @@ safe_syscall_base:
* does not list any ABI differences regarding stack alignment.)
+ .cfi_def_cfa_offset 16
+ .cfi_offset rbp,-16
While this is correct, there are two other directives that make it easier to
describe changes without having to compute globally correct constants. Here
they would be:
Add 8 to the offset, i.e. decrement the SP by 8.
.cfi_rel_offset rbp, 0
Save rbp at the current top-of-stack.
The assembler will compute the absolute values from these relative values.
Using them makes it easy to see from a narrow window of code that the
annotations are correct.
Reviewed-by: Richard Henderson <address@hidden>