diff options
Diffstat (limited to 'tools/include')
| -rw-r--r-- | tools/include/nolibc/arch-arm.h | 60 |
1 files changed, 47 insertions, 13 deletions
diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h index e4ba77b0310f..ef94df2d93d5 100644 --- a/tools/include/nolibc/arch-arm.h +++ b/tools/include/nolibc/arch-arm.h @@ -70,20 +70,44 @@ struct sys_stat_struct { * don't have to experience issues with register constraints. * - the syscall number is always specified last in order to allow to force * some registers before (gcc refuses a %-register at the last position). + * - in thumb mode without -fomit-frame-pointer, r7 is also used to store the + * frame pointer, and we cannot directly assign it as a register variable, + * nor can we clobber it. Instead we assign the r6 register and swap it + * with r7 before calling svc, and r6 is marked as clobbered. + * We're just using any regular register which we assign to r7 after saving + * it. * * Also, ARM supports the old_select syscall if newselect is not available */ #define __ARCH_WANT_SYS_OLD_SELECT +#if (defined(__THUMBEB__) || defined(__THUMBEL__)) && \ + !defined(NOLIBC_OMIT_FRAME_POINTER) +/* swap r6,r7 needed in Thumb mode since we can't use nor clobber r7 */ +#define _NOLIBC_SYSCALL_REG "r6" +#define _NOLIBC_THUMB_SET_R7 "eor r7, r6\neor r6, r7\neor r7, r6\n" +#define _NOLIBC_THUMB_RESTORE_R7 "mov r7, r6\n" + +#else /* we're in ARM mode */ +/* in Arm mode we can directly use r7 */ +#define _NOLIBC_SYSCALL_REG "r7" +#define _NOLIBC_THUMB_SET_R7 "" +#define _NOLIBC_THUMB_RESTORE_R7 "" + +#endif /* end THUMB */ + #define my_syscall0(num) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0"); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r"(_arg1) \ - : "r"(_num) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r"(_num) \ + : "r"(_arg1), \ + "r"(_num) \ : "memory", "cc", "lr" \ ); \ _arg1; \ @@ -91,12 +115,14 @@ struct sys_stat_struct { #define my_syscall1(num, arg1) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0") = (long)(arg1); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r"(_arg1) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r" (_num) \ : "r"(_arg1), \ "r"(_num) \ : "memory", "cc", "lr" \ @@ -106,13 +132,15 @@ struct sys_stat_struct { #define my_syscall2(num, arg1, arg2) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0") = (long)(arg1); \ register long _arg2 __asm__ ("r1") = (long)(arg2); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r"(_arg1) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r" (_num) \ : "r"(_arg1), "r"(_arg2), \ "r"(_num) \ : "memory", "cc", "lr" \ @@ -122,14 +150,16 @@ struct sys_stat_struct { #define my_syscall3(num, arg1, arg2, arg3) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0") = (long)(arg1); \ register long _arg2 __asm__ ("r1") = (long)(arg2); \ register long _arg3 __asm__ ("r2") = (long)(arg3); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r"(_arg1) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r" (_num) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), \ "r"(_num) \ : "memory", "cc", "lr" \ @@ -139,15 +169,17 @@ struct sys_stat_struct { #define my_syscall4(num, arg1, arg2, arg3, arg4) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0") = (long)(arg1); \ register long _arg2 __asm__ ("r1") = (long)(arg2); \ register long _arg3 __asm__ ("r2") = (long)(arg3); \ register long _arg4 __asm__ ("r3") = (long)(arg4); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r"(_arg1) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r" (_num) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ "r"(_num) \ : "memory", "cc", "lr" \ @@ -157,7 +189,7 @@ struct sys_stat_struct { #define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ ({ \ - register long _num __asm__ ("r7") = (num); \ + register long _num __asm__(_NOLIBC_SYSCALL_REG) = (num); \ register long _arg1 __asm__ ("r0") = (long)(arg1); \ register long _arg2 __asm__ ("r1") = (long)(arg2); \ register long _arg3 __asm__ ("r2") = (long)(arg3); \ @@ -165,8 +197,10 @@ struct sys_stat_struct { register long _arg5 __asm__ ("r4") = (long)(arg5); \ \ __asm__ volatile ( \ + _NOLIBC_THUMB_SET_R7 \ "svc #0\n" \ - : "=r" (_arg1) \ + _NOLIBC_THUMB_RESTORE_R7 \ + : "=r"(_arg1), "=r" (_num) \ : "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \ "r"(_num) \ : "memory", "cc", "lr" \ |