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clean up mips64/n32 syscall asm constraints 

ever since inline syscalls were added for (o32) mips in commit
328810d325, the asm has nonsensically
loaded the syscall number, rather than taking $2 as an input
constraint to let the compiler load it. commit
cfc09b1ecf improved on this somewhat by
allowing a constant syscall number to propagate into an immediate, but
missed that the whole operation made no sense.

now, only $4, $5, $6, $8, and $9 are potential input-only registers.
$2 is always input and output, and $7 is both when it's an argument,
otherwise output-only. previously, $7 was treated as an input (with a
"1" constraint matching its output position) even when it was not an
input, which was arguably undefined behavior (asm input from
indeterminate value). this is corrected.
This commit is contained in:
Rich Felker 2019-07-16 20:49:02 -04:00
parent db2a148d9d
commit ddc7c4f936
2 changed files with 56 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
arch/mips64/syscall_arch.h
View File

@ -53,10 +53,11 @@ static void __stat_fix(struct kernel_stat *kst, struct stat *st)
static inline long __syscall0(long n)
{
register long r7 __asm__("$7");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7)
"syscall"
: "+&r"(r2), "=r"(r7)
:
: SYSCALL_CLOBBERLIST);
return r7 ? -r2 : r2;
}
@ -65,11 +66,11 @@ static inline long __syscall1(long n, long a)
{
register long r4 __asm__("$4") = a;
register long r7 __asm__("$7");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4)
: SYSCALL_CLOBBERLIST);
return r7 ? -r2 : r2;
}
@ -81,15 +82,15 @@ 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");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat)
r5 = (long) &kst;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4), "r"(r5)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
@ -109,15 +110,15 @@ 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");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat)
r5 = (long) &kst;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4), "r"(r5), "r"(r6)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
@ -137,7 +138,7 @@ 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;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat)
r5 = (long) &kst;
@ -145,9 +146,9 @@ static inline long __syscall4(long n, long a, long b, long c, long d)
r6 = (long) &kst;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
@ -170,7 +171,7 @@ static inline long __syscall5(long n, long a, long b, long c, long d, long e)
register long r6 __asm__("$6") = c;
register long r7 __asm__("$7") = d;
register long r8 __asm__("$8") = e;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat)
r5 = (long) &kst;
@ -178,9 +179,9 @@ static inline long __syscall5(long n, long a, long b, long c, long d, long e)
r6 = (long) &kst;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6), "r"(r8)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6), "r"(r8)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
@ -204,7 +205,7 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
register long r7 __asm__("$7") = d;
register long r8 __asm__("$8") = e;
register long r9 __asm__("$9") = f;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat)
r5 = (long) &kst;
@ -212,9 +213,9 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
r6 = (long) &kst;
__asm__ __volatile__ (
"daddu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6), "r"(r8), "r"(r9)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6), "r"(r8), "r"(r9)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;

55
arch/mipsn32/syscall_arch.h
View File

@ -22,10 +22,11 @@ static inline void __stat_fix(long p)
static inline long __syscall0(long n)
{
register long r7 __asm__("$7");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7)
"syscall"
: "+&r"(r2), "=r"(r7)
:
: SYSCALL_CLOBBERLIST);
return r7 ? -r2 : r2;
}
@ -34,11 +35,11 @@ static inline long __syscall1(long n, long a)
{
register long r4 __asm__("$4") = a;
register long r7 __asm__("$7");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4)
: SYSCALL_CLOBBERLIST);
return r7 ? -r2 : r2;
}
@ -48,11 +49,11 @@ 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");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4), "r"(r5)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
long ret = r2;
@ -66,11 +67,11 @@ 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");
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
"syscall"
: "+&r"(r2), "=r"(r7)
: "r"(r4), "r"(r5), "r"(r6)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
long ret = r2;
@ -84,11 +85,11 @@ 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;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6)
: SYSCALL_CLOBBERLIST);
if (r7) return -r2;
long ret = r2;
@ -104,11 +105,11 @@ static inline long __syscall5(long n, long a, long b, long c, long d, long e)
register long r6 __asm__("$6") = c;
register long r7 __asm__("$7") = d;
register long r8 __asm__("$8") = e;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6), "r"(r8)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6), "r"(r8)
: SYSCALL_CLOBBERLIST);
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat) __stat_fix(b);
if (n == SYS_newfstatat) __stat_fix(c);
@ -123,11 +124,11 @@ static inline long __syscall6(long n, long a, long b, long c, long d, long e, lo
register long r7 __asm__("$7") = d;
register long r8 __asm__("$8") = e;
register long r9 __asm__("$9") = f;
register long r2 __asm__("$2");
register long r2 __asm__("$2") = n;
__asm__ __volatile__ (
"addu $2,$0,%2 ; syscall"
: "=&r"(r2), "=r"(r7) : "ir"(n), "0"(r2), "1"(r7),
"r"(r4), "r"(r5), "r"(r6), "r"(r8), "r"(r9)
"syscall"
: "+&r"(r2), "+r"(r7)
: "r"(r4), "r"(r5), "r"(r6), "r"(r8), "r"(r9)
: SYSCALL_CLOBBERLIST);
if (n == SYS_stat || n == SYS_fstat || n == SYS_lstat) __stat_fix(b);
if (n == SYS_newfstatat) __stat_fix(c);