x86-64: Cast __rseq_offset to long long int [BZ #32543]

commit 494d65129ed5ae1154b75cc189bbdde5e9ecf1df
Author: Michael Jeanson <mjeanson@efficios.com>
Date:   Thu Aug 1 10:35:34 2024 -0400

    nptl: Introduce <rseq-access.h> for RSEQ_* accessors

added things like

       asm volatile ("movl %%fs:%P1(%q2),%0"                                  \
                     : "=r" (__value)                                         \
                     : "i" (offsetof (struct rseq_area, member)),             \
                       "r" (__rseq_offset));				      \

But this doesn't work for x32 when __rseq_offset is negative since the
address is computed as

FS + 32-bit to 64-bit zero extension of __rseq_offset
+ offsetof (struct rseq_area, member)

Cast __rseq_offset to long long int

                       "r" ((long long int) __rseq_offset));		      \

to sign-extend 32-bit __rseq_offset to 64-bit.  This is a no-op for x86-64
since x86-64 __rseq_offset is 64-bit.  This fixes BZ #32543.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>

diff --git a/sysdeps/x86_64/nptl/rseq-access.h b/sysdeps/x86_64/nptl/rseq-access.h
index 535e36281fba52b693a0a99f72b8916190519649..bc966b2972d18ee524626d85bd17096beb2c5e98 100644 (file)
--- a/sysdeps/x86_64/nptl/rseq-access.h
+++ b/sysdeps/x86_64/nptl/rseq-access.h
@@ -27,18 +27,18 @@
        asm volatile ("movb %%fs:%P2(%q3),%b0"                                \
                     : "=q" (__value)                                         \
                     : "0" (0), "i" (offsetof (struct rseq_area, member)),    \
-                      "r" (__rseq_offset));                                  \
+                      "r" ((long long int) __rseq_offset));                  \
      else if (sizeof (__value) == 4)                                         \
        asm volatile ("movl %%fs:%P1(%q2),%0"                                 \
                     : "=r" (__value)                                         \
                     : "i" (offsetof (struct rseq_area, member)),             \
-                      "r" (__rseq_offset));                                  \
+                      "r" ((long long int) __rseq_offset));                  \
      else /* 8 */                                                            \
        {                                                                     \
         asm volatile ("movq %%fs:%P1(%q2),%q0"                               \
                       : "=r" (__value)                                       \
                       : "i" (offsetof (struct rseq_area, member)),           \
-                        "r" (__rseq_offset));                                \
+                        "r" ((long long int) __rseq_offset));                \
        }                                                                     \
      __value; })
 
@@ -56,12 +56,12 @@
        asm volatile ("movb %b0,%%fs:%P1(%q2)" :                                      \
                     : "iq" (value),                                          \
                       "i" (offsetof (struct rseq_area, member)),             \
-                      "r" (__rseq_offset));                                  \
+                      "r" ((long long int) __rseq_offset));                  \
      else if (sizeof (RSEQ_SELF()->member) == 4)                             \
        asm volatile ("movl %0,%%fs:%P1(%q2)" :                               \
                     : IMM_MODE (value),                                      \
                       "i" (offsetof (struct rseq_area, member)),             \
-                      "r" (__rseq_offset));                                  \
+                      "r" ((long long int) __rseq_offset));                  \
      else /* 8 */                                                            \
        {                                                                     \
         /* Since movq takes a signed 32-bit immediate or a register source   \
@@ -70,7 +70,7 @@
         asm volatile ("movq %q0,%%fs:%P1(%q2)" :                             \
                       : "er" ((uint64_t) cast_to_integer (value)),           \
                         "i" (offsetof (struct rseq_area, member)),           \
-                        "r" (__rseq_offset));                                \
+                        "r" ((long long int) __rseq_offset));                \
        }})
 
 /* Set member of the RSEQ area directly.  */