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

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commit 494d65129e
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>
This commit is contained in:
H.J. Lu 2025-01-11 22:57:02 +08:00
parent 53a71b9f66
commit 0b6ad02b33
1 changed files with 6 additions and 6 deletions
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12
sysdeps/x86_64/nptl/rseq-access.h
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@ -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. */