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fix mips struct stat dev_t members for big endian

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the mips version of this structure on the kernel side wrongly has
32-bit type rather than 64-bit type. fortunately there is adjacent
padding to bring it up to 64 bits, and on little-endian, this allows
us to treat the adjacent kernel st_dev and st_pad0[0] as as single
64-bit dev_t. however, on big endian, such treatment results in the
upper and lower 32-bit parts of the dev_t value being swapped. for the
purpose of just comparing st_dev values this did not break anything,
but it precluded actually processing the device numbers as major/minor
values.

since the broken kernel behavior that needs to be worked around is
isolated to one arch, I put the workarounds in syscall_arch.h rather
than adding a stat fixup path in the common code. on little endian
mips, the added code optimizes out completely.

the changes necessary were incompatible with the way the __asm_syscall
macro was factored so I just removed it and flattened the individual
__syscallN functions. this arguably makes the code easier to read and
understand, anyway.
This commit is contained in:
Rich Felker 2014-07-19 23:37:21 -04:00
parent ddddec106f
commit f61be1f875
1 changed files with 81 additions and 20 deletions
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101
arch/mips/syscall_arch.h
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@ -7,29 +7,44 @@ long (__syscall)(long, ...);
#define SYSCALL_RLIM_INFINITY (-1UL/2)
#ifndef __clang__
#if _MIPSEL || __MIPSEL || __MIPSEL__
#define __stat_fix(st) ((st),(void)0)
#else
#include <sys/stat.h>
static inline void __stat_fix(long p)
{
struct stat *st = (struct stat *)p;
st->st_dev >>= 32;
st->st_rdev >>= 32;
}
#endif
#define __asm_syscall(...) do { \
register long r2 __asm__("$2"); \
__asm__ __volatile__ ( \
"addu $2,$0,%2 ; syscall" \
: "=&r"(r2), "=r"(r7) : "ir"(n), __VA_ARGS__, "0"(r2), "1"(r7) \
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13", \
"$14", "$15", "$24", "$25", "hi", "lo", "memory"); \
return r7 ? -r2 : r2; \
} while (0)
#ifndef __clang__
static inline long __syscall0(long n)
{
register long r7 __asm__("$7");
__asm_syscall("i"(0));
register long r2 __asm__("$2");
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7)
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
"$14", "$15", "$24", "$25", "hi", "lo", "memory");
return r7 ? -r2 : r2;
}
static inline long __syscall1(long n, long a)
{
register long r4 __asm__("$4") = a;
register long r7 __asm__("$7");
__asm_syscall("r"(r4));
register long r2 __asm__("$2");
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4)
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
"$14", "$15", "$24", "$25", "hi", "lo", "memory");
return r7 ? -r2 : r2;
}
static inline long __syscall2(long n, long a, long b)
@ -37,7 +52,16 @@ static inline long __syscall2(long n, long a, long b)
register long r4 __asm__("$4") = a;
register long r5 __asm__("$5") = b;
register long r7 __asm__("$7");
__asm_syscall("r"(r4), "r"(r5));
register long r2 __asm__("$2");
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5)
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
"$14", "$15", "$24", "$25", "hi", "lo", "memory");
if (r7) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
return r2;
}
static inline long __syscall3(long n, long a, long b, long c)
@ -46,7 +70,16 @@ static inline long __syscall3(long n, long a, long b, long c)
register long r5 __asm__("$5") = b;
register long r6 __asm__("$6") = c;
register long r7 __asm__("$7");
__asm_syscall("r"(r4), "r"(r5), "r"(r6));
register long r2 __asm__("$2");
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
"$14", "$15", "$24", "$25", "hi", "lo", "memory");
if (r7) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
return r2;
}
static inline long __syscall4(long n, long a, long b, long c, long d)
@ -55,7 +88,17 @@ static inline long __syscall4(long n, long a, long b, long c, long d)
register long r5 __asm__("$5") = b;
register long r6 __asm__("$6") = c;
register long r7 __asm__("$7") = d;
__asm_syscall("r"(r4), "r"(r5), "r"(r6));
register long r2 __asm__("$2");
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
: "$1", "$3", "$8", "$9", "$10", "$11", "$12", "$13",
"$14", "$15", "$24", "$25", "hi", "lo", "memory");
if (r7) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
if (n == SYS_fstatat) __stat_fix(c);
return r2;
}
#else
@ -72,27 +115,45 @@ static inline long __syscall1(long n, long a)
static inline long __syscall2(long n, long a, long b)
{
return (__syscall)(n, a, b);
long r2 = (__syscall)(n, a, b);
if (r2 > -4096UL) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
return r2;
}
static inline long __syscall3(long n, long a, long b, long c)
{
return (__syscall)(n, a, b, c);
long r2 = (__syscall)(n, a, b, c);
if (r2 > -4096UL) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
return r2;
}
static inline long __syscall4(long n, long a, long b, long c, long d)
{
return (__syscall)(n, a, b, c, d);
long r2 = (__syscall)(n, a, b, c, d);
if (r2 > -4096UL) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
if (n == SYS_fstatat) __stat_fix(c);
return r2;
}
#endif
static inline long __syscall5(long n, long a, long b, long c, long d, long e)
{
return (__syscall)(n, a, b, c, d, e);
long r2 = (__syscall)(n, a, b, c, d, e);
if (r2 > -4096UL) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
if (n == SYS_fstatat) __stat_fix(c);
return r2;
}
static inline long __syscall6(long n, long a, long b, long c, long d, long e, long f)
{
return (__syscall)(n, a, b, c, d, e, f);
long r2 = (__syscall)(n, a, b, c, d, e, f);
if (r2 > -4096UL) return -r2;
if (n == SYS_stat64 || n == SYS_fstat64 || n == SYS_lstat64) __stat_fix(b);
if (n == SYS_fstatat) __stat_fix(c);
return r2;
}