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remove x32 syscall timespec fixup hacks 

the x32 syscall interfaces treat timespec's tv_nsec member as 64-bit
despite the API type being long and long being 32-bit in the ABI. this
is no problem for syscalls that store timespecs to userspace as
results, but caused uninitialized padding to be misinterpreted as the
high bits in syscalls that take timespecs as input.

since the beginning of the port, we've dealt with this situation with
hacks in syscall_arch.h, and injected between __syscall_cp_c and
__syscall_cp_asm, to special-case the syscall numbers that involve
timespecs as inputs and copy them to a form suitable to pass to the
kernel.

commit 40aa18d55a set the stage for
removal of these hacks by letting us treat the "normal" x32 syscalls
dealing with timespec as if they're x32's "time64" syscalls,
effectively making x32 ax "time64-only 32-bit arch" like riscv32 will
be when it's added. since then, all users of syscalls that x32's
syscall_arch.h had hacks for have been updated to use time64 syscalls,
so the hacks can be removed.

there are still at least a few other timespec-related syscalls broken
on x32, which were overlooked when the x32 hacks were done or added
later. these include at least recvmmsg, adjtimex/clock_adjtime, and
timerfd_settime, and they will be fixed independently later on.
This commit is contained in:
Rich Felker 2019-07-28 19:29:28 -04:00
parent 01f3480d37
commit 4c307bed03
3 changed files with 4 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
arch/x32/syscall_arch.h
View File

@ -3,35 +3,6 @@
#define __scc(X) sizeof(1?(X):0ULL) < 8 ? (unsigned long) (X) : (long long) (X) #define __scc(X) sizeof(1?(X):0ULL) < 8 ? (unsigned long) (X) : (long long) (X)
typedef long long syscall_arg_t; typedef long long syscall_arg_t;
struct __timespec { long long tv_sec; long tv_nsec; };
struct __timespec_kernel { long long tv_sec; long long tv_nsec; };
#define __tsc(X) ((struct __timespec*)(unsigned long)(X))
#define __fixup(X) do { if(X) { \
ts->tv_sec = __tsc(X)->tv_sec; \
ts->tv_nsec = __tsc(X)->tv_nsec; \
(X) = (unsigned long)ts; } } while(0)
#define __fixup_case_2 \
case SYS_nanosleep: \
__fixup(a1); break; \
case SYS_clock_settime: \
__fixup(a2); break;
#define __fixup_case_3 \
case SYS_clock_nanosleep: case SYS_rt_sigtimedwait: case SYS_ppoll: \
__fixup(a3); break; \
case SYS_utimensat: \
if(a3) { \
ts[0].tv_sec = __tsc(a3)[0].tv_sec; \
ts[0].tv_nsec = __tsc(a3)[0].tv_nsec; \
ts[1].tv_sec = __tsc(a3)[1].tv_sec; \
ts[1].tv_nsec = __tsc(a3)[1].tv_nsec; \
a3 = (unsigned long)ts; \
} break;
#define __fixup_case_4 \
case SYS_futex: \
if((a2 & (~128 /* FUTEX_PRIVATE_FLAG */)) == 0 /* FUTEX_WAIT */) __fixup(a4); break;
#define __fixup_case_5 \
case SYS_mq_timedsend: case SYS_mq_timedreceive: case SYS_pselect6: \
__fixup(a5); break;
static __inline long __syscall0(long long n) static __inline long __syscall0(long long n)
{ {
@ -50,10 +21,6 @@ static __inline long __syscall1(long long n, long long a1)
static __inline long __syscall2(long long n, long long a1, long long a2) static __inline long __syscall2(long long n, long long a1, long long a2)
{ {
unsigned long ret; unsigned long ret;
struct __timespec_kernel ts[1];
switch (n) {
__fixup_case_2;
}
__asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2) __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2)
: "rcx", "r11", "memory"); : "rcx", "r11", "memory");
return ret; return ret;
@ -62,11 +29,6 @@ static __inline long __syscall2(long long n, long long a1, long long a2)
static __inline long __syscall3(long long n, long long a1, long long a2, long long a3) static __inline long __syscall3(long long n, long long a1, long long a2, long long a3)
{ {
unsigned long ret; unsigned long ret;
struct __timespec_kernel ts[2];
switch (n) {
__fixup_case_2;
__fixup_case_3;
}
__asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
"d"(a3) : "rcx", "r11", "memory"); "d"(a3) : "rcx", "r11", "memory");
return ret; return ret;
@ -77,12 +39,6 @@ static __inline long __syscall4(long long n, long long a1, long long a2, long lo
{ {
unsigned long ret; unsigned long ret;
register long long a4 __asm__("r10") = a4_; register long long a4 __asm__("r10") = a4_;
struct __timespec_kernel ts[2];
switch (n) {
__fixup_case_2;
__fixup_case_3;
__fixup_case_4;
}
__asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
"d"(a3), "r"(a4): "rcx", "r11", "memory"); "d"(a3), "r"(a4): "rcx", "r11", "memory");
return ret; return ret;
@ -94,13 +50,6 @@ static __inline long __syscall5(long long n, long long a1, long long a2, long lo
unsigned long ret; unsigned long ret;
register long long a4 __asm__("r10") = a4_; register long long a4 __asm__("r10") = a4_;
register long long a5 __asm__("r8") = a5_; register long long a5 __asm__("r8") = a5_;
struct __timespec_kernel ts[2];
switch (n) {
__fixup_case_2;
__fixup_case_3;
__fixup_case_4;
__fixup_case_5;
}
__asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
"d"(a3), "r"(a4), "r"(a5) : "rcx", "r11", "memory"); "d"(a3), "r"(a4), "r"(a5) : "rcx", "r11", "memory");
return ret; return ret;
@ -113,13 +62,6 @@ static __inline long __syscall6(long long n, long long a1, long long a2, long lo
register long long a4 __asm__("r10") = a4_; register long long a4 __asm__("r10") = a4_;
register long long a5 __asm__("r8") = a5_; register long long a5 __asm__("r8") = a5_;
register long long a6 __asm__("r9") = a6_; register long long a6 __asm__("r9") = a6_;
struct __timespec_kernel ts[2];
switch (n) {
__fixup_case_2;
__fixup_case_3;
__fixup_case_4;
__fixup_case_5;
}
__asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2), __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
"d"(a3), "r"(a4), "r"(a5), "r"(a6) : "rcx", "r11", "memory"); "d"(a3), "r"(a4), "r"(a5), "r"(a6) : "rcx", "r11", "memory");
return ret; return ret;

8
src/thread/x32/syscall_cp.s
View File

@ -6,10 +6,10 @@
.global __cp_cancel .global __cp_cancel
.hidden __cp_cancel .hidden __cp_cancel
.hidden __cancel .hidden __cancel
.global __syscall_cp_internal .global __syscall_cp_asm
.hidden __syscall_cp_internal .hidden __syscall_cp_asm
.type __syscall_cp_internal,@function .type __syscall_cp_asm,@function
__syscall_cp_internal: __syscall_cp_asm:
__cp_begin: __cp_begin:
mov (%rdi),%eax mov (%rdi),%eax

39
src/thread/x32/syscall_cp_fixup.c
View File

@ -1,39 +0,0 @@
#include <sys/syscall.h>
#include <features.h>
hidden long __syscall_cp_internal(volatile void*, long long, long long,
long long, long long, long long,
long long, long long);
struct __timespec { long long tv_sec; long tv_nsec; };
struct __timespec_kernel { long long tv_sec; long long tv_nsec; };
#define __tsc(X) ((struct __timespec*)(unsigned long)(X))
#define __fixup(X) do { if(X) { \
ts->tv_sec = __tsc(X)->tv_sec; \
ts->tv_nsec = __tsc(X)->tv_nsec; \
(X) = (unsigned long)ts; } } while(0)
hidden long __syscall_cp_asm (volatile void * foo, long long n, long long a1,
long long a2, long long a3, long long a4,
long long a5, long long a6)
{
struct __timespec_kernel ts[1];
switch (n) {
case SYS_mq_timedsend: case SYS_mq_timedreceive: case SYS_pselect6:
__fixup(a5);
break;
case SYS_futex:
if((a2 & (~128 /* FUTEX_PRIVATE_FLAG */)) == 0 /* FUTEX_WAIT */)
__fixup(a4);
break;
case SYS_clock_nanosleep:
case SYS_rt_sigtimedwait: case SYS_ppoll:
__fixup(a3);
break;
case SYS_nanosleep:
__fixup(a1);
break;
}
return __syscall_cp_internal(foo, n, a1, a2, a3, a4, a5, a6);
}