From: Paul Floyd <pjfloyd@wanadoo.fr>
Date: Thu, 9 Dec 2021 21:11:04 +0000 (+0100)
Subject: Minor sigreturn code cleaning for sigreturn / FreeBSD
X-Git-Tag: VALGRIND_3_19_0~54
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3bfe4a4f7afa6681415f46eb473c244e95efaafa;p=thirdparty%2Fvalgrind.git

Minor sigreturn code cleaning for sigreturn / FreeBSD

More comments + wrapper arg names matching man page
(even if the syscall should never get called directly
from client code).
---

diff --git a/coregrind/m_syswrap/syswrap-amd64-freebsd.c b/coregrind/m_syswrap/syswrap-amd64-freebsd.c
index 076f5b4c4d..c5685c4773 100644
--- a/coregrind/m_syswrap/syswrap-amd64-freebsd.c
+++ b/coregrind/m_syswrap/syswrap-amd64-freebsd.c
@@ -424,8 +424,8 @@ PRE(sys_sigreturn)
    PRE_REG_READ1(int, "sigreturn",
                  struct vki_ucontext *, ucp);
 
-   PRE_MEM_READ( "sigreturn(ucp)", ARG1, sizeof(struct vki_ucontext) );
-   PRE_MEM_WRITE( "sigreturn(ucp)", ARG1, sizeof(struct vki_ucontext) );
+   PRE_MEM_READ( "sigreturn(scp)", ARG1, sizeof(struct vki_ucontext) );
+   PRE_MEM_WRITE( "sigreturn(scp)", ARG1, sizeof(struct vki_ucontext) );
 }
 
 static void restore_mcontext(ThreadState *tst, struct vki_mcontext *sc)
diff --git a/coregrind/m_syswrap/syswrap-x86-freebsd.c b/coregrind/m_syswrap/syswrap-x86-freebsd.c
index 0c8da316f9..4fd1ce5011 100644
--- a/coregrind/m_syswrap/syswrap-x86-freebsd.c
+++ b/coregrind/m_syswrap/syswrap-x86-freebsd.c
@@ -1468,10 +1468,10 @@ PRE(sys_fake_sigreturn)
    struct vki_ucontext *uc;
    PRINT("sys_sigreturn ( %#" FMT_REGWORD "x )", ARG1);
    PRE_REG_READ1(long, "sigreturn",
-                 struct vki_ucontext *, ucp);
+                 struct vki_ucontext *, scp);
 
-   PRE_MEM_READ( "sigreturn(ucp)", ARG1, sizeof(struct vki_ucontext) );
-   PRE_MEM_WRITE( "sigreturn(ucp)", ARG1, sizeof(struct vki_ucontext) );
+   PRE_MEM_READ( "sigreturn(scp)", ARG1, sizeof(struct vki_ucontext) );
+   PRE_MEM_WRITE( "sigreturn(scp)", ARG1, sizeof(struct vki_ucontext) );
 
    vg_assert(VG_(is_valid_tid)(tid));
    vg_assert(tid >= 1 && tid < VG_N_THREADS);
diff --git a/coregrind/m_trampoline.S b/coregrind/m_trampoline.S
index ad1db3cb9f..da96972323 100644
--- a/coregrind/m_trampoline.S
+++ b/coregrind/m_trampoline.S
@@ -899,7 +899,29 @@ VG_(trampoline_stuff_start):
 VG_(amd64_freebsd_SUBST_FOR_sigreturn):
         /* This is a very specific sequence which GDB uses to
            recognize signal handler frames. */
+
         movq    $__NR_fake_sigreturn, %rax
+
+        /* running the preprocessor on
+         * src/amd64.amd64/lib/libc/sigreturn.S
+         * gives
+         * .text; .p2align 4,0x90; .globl __sys_sigreturn;
+         * .type __sys_sigreturn,@function; __sys_sigreturn:;
+         * .cfi_startproc; .weak sigreturn; .equ sigreturn,__sys_sigreturn;
+         *  .weak _sigreturn; .equ _sigreturn,__sys_sigreturn;
+         *  mov $417,%eax;
+         * movq %rcx, %r10;
+         * syscall; jb .cerror; ret; .size __sys_sigreturn, . - __sys_sigreturn;
+         *  .cfi_endproc
+         */
+
+        /*
+         * sigframe in sigframe-amd64-freebsd.c
+         * differs from sigframe in /usr/include/x86/sigframe.h
+         * by having the address to this trampoline first
+         * so I assume that the +8 is to get back to the
+         * FreeBSD sigframe
+         */
         movq	%rsp, %rdi
         addq	$8,%rdi
         syscall