| Message ID | 20220729172141.1789105-2-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Re-enable ppc32 as a linux-user host | expand |
On 7/29/22 14:21, Richard Henderson wrote: > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com> > common-user/host/ppc/safe-syscall.inc.S | 107 ++++++++++++++++++++++++ > 1 file changed, 107 insertions(+) > create mode 100644 common-user/host/ppc/safe-syscall.inc.S > > diff --git a/common-user/host/ppc/safe-syscall.inc.S b/common-user/host/ppc/safe-syscall.inc.S > new file mode 100644 > index 0000000000..0851f6c0b8 > --- /dev/null > +++ b/common-user/host/ppc/safe-syscall.inc.S > @@ -0,0 +1,107 @@ > +/* > + * safe-syscall.inc.S : host-specific assembly fragment > + * to handle signals occurring at the same time as system calls. > + * This is intended to be included by common-user/safe-syscall.S > + * > + * Copyright (C) 2022 Linaro, Ltd. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +/* > + * Standardize on the _CALL_FOO symbols used by GCC: > + * Apple XCode does not define _CALL_DARWIN. > + * Clang defines _CALL_ELF (64-bit) but not _CALL_SYSV (32-bit). > + */ > +#if !defined(_CALL_SYSV) && \ > + !defined(_CALL_DARWIN) && \ > + !defined(_CALL_AIX) && \ > + !defined(_CALL_ELF) > +# if defined(__APPLE__) > +# define _CALL_DARWIN > +# elif defined(__ELF__) && TCG_TARGET_REG_BITS == 32 > +# define _CALL_SYSV > +# else > +# error "Unknown ABI" > +# endif > +#endif > + > +#ifndef _CALL_SYSV > +# error "Unsupported ABI" > +#endif > + > + > + .global safe_syscall_base > + .global safe_syscall_start > + .global safe_syscall_end > + .type safe_syscall_base, @function > + > + .text > + > + /* > + * This is the entry point for making a system call. The calling > + * convention here is that of a C varargs function with the > + * first argument an 'int *' to the signal_pending flag, the > + * second one the system call number (as a 'long'), and all further > + * arguments being syscall arguments (also 'long'). > + */ > +safe_syscall_base: > + .cfi_startproc > + stwu 1, -8(1) > + .cfi_def_cfa_offset 8 > + stw 30, 4(1) > + .cfi_offset 30, -4 > + > + /* > + * We enter with r3 == &signal_pending > + * r4 == syscall number > + * r5 ... r10 == syscall arguments > + * and return the result in r3 > + * and the syscall instruction needs > + * r0 == syscall number > + * r3 ... r8 == syscall arguments > + * and returns the result in r3 > + * Shuffle everything around appropriately. > + */ > + mr 30, 3 /* signal_pending */ > + mr 0, 4 /* syscall number */ > + mr 3, 5 /* syscall arguments */ > + mr 4, 6 > + mr 5, 7 > + mr 6, 8 > + mr 7, 9 > + mr 8, 10 > + > + /* > + * This next sequence of code works in conjunction with the > + * rewind_if_safe_syscall_function(). If a signal is taken > + * and the interrupted PC is anywhere between 'safe_syscall_start' > + * and 'safe_syscall_end' then we rewind it to 'safe_syscall_start'. > + * The code sequence must therefore be able to cope with this, and > + * the syscall instruction must be the final one in the sequence. > + */ > +safe_syscall_start: > + /* if signal_pending is non-zero, don't do the call */ > + lwz 12, 0(30) > + cmpwi 0, 12, 0 > + bne- 2f > + sc > +safe_syscall_end: > + /* code path when we did execute the syscall */ > + lwz 30, 4(1) /* restore r30 */ > + addi 1, 1, 8 /* restore stack */ > + .cfi_restore 30 > + .cfi_def_cfa_offset 0 > + bnslr+ /* return on success */ > + b safe_syscall_set_errno_tail > + > + /* code path when we didn't execute the syscall */ > +2: lwz 30, 4(1) > + addi 1, 1, 8 > + addi 3, 0, QEMU_ERESTARTSYS > + b safe_syscall_set_errno_tail > + > + .cfi_endproc > + > + .size safe_syscall_base, .-safe_syscall_base
diff --git a/common-user/host/ppc/safe-syscall.inc.S b/common-user/host/ppc/safe-syscall.inc.S new file mode 100644 index 0000000000..0851f6c0b8 --- /dev/null +++ b/common-user/host/ppc/safe-syscall.inc.S @@ -0,0 +1,107 @@ +/* + * safe-syscall.inc.S : host-specific assembly fragment + * to handle signals occurring at the same time as system calls. + * This is intended to be included by common-user/safe-syscall.S + * + * Copyright (C) 2022 Linaro, Ltd. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +/* + * Standardize on the _CALL_FOO symbols used by GCC: + * Apple XCode does not define _CALL_DARWIN. + * Clang defines _CALL_ELF (64-bit) but not _CALL_SYSV (32-bit). + */ +#if !defined(_CALL_SYSV) && \ + !defined(_CALL_DARWIN) && \ + !defined(_CALL_AIX) && \ + !defined(_CALL_ELF) +# if defined(__APPLE__) +# define _CALL_DARWIN +# elif defined(__ELF__) && TCG_TARGET_REG_BITS == 32 +# define _CALL_SYSV +# else +# error "Unknown ABI" +# endif +#endif + +#ifndef _CALL_SYSV +# error "Unsupported ABI" +#endif + + + .global safe_syscall_base + .global safe_syscall_start + .global safe_syscall_end + .type safe_syscall_base, @function + + .text + + /* + * This is the entry point for making a system call. The calling + * convention here is that of a C varargs function with the + * first argument an 'int *' to the signal_pending flag, the + * second one the system call number (as a 'long'), and all further + * arguments being syscall arguments (also 'long'). + */ +safe_syscall_base: + .cfi_startproc + stwu 1, -8(1) + .cfi_def_cfa_offset 8 + stw 30, 4(1) + .cfi_offset 30, -4 + + /* + * We enter with r3 == &signal_pending + * r4 == syscall number + * r5 ... r10 == syscall arguments + * and return the result in r3 + * and the syscall instruction needs + * r0 == syscall number + * r3 ... r8 == syscall arguments + * and returns the result in r3 + * Shuffle everything around appropriately. + */ + mr 30, 3 /* signal_pending */ + mr 0, 4 /* syscall number */ + mr 3, 5 /* syscall arguments */ + mr 4, 6 + mr 5, 7 + mr 6, 8 + mr 7, 9 + mr 8, 10 + + /* + * This next sequence of code works in conjunction with the + * rewind_if_safe_syscall_function(). If a signal is taken + * and the interrupted PC is anywhere between 'safe_syscall_start' + * and 'safe_syscall_end' then we rewind it to 'safe_syscall_start'. + * The code sequence must therefore be able to cope with this, and + * the syscall instruction must be the final one in the sequence. + */ +safe_syscall_start: + /* if signal_pending is non-zero, don't do the call */ + lwz 12, 0(30) + cmpwi 0, 12, 0 + bne- 2f + sc +safe_syscall_end: + /* code path when we did execute the syscall */ + lwz 30, 4(1) /* restore r30 */ + addi 1, 1, 8 /* restore stack */ + .cfi_restore 30 + .cfi_def_cfa_offset 0 + bnslr+ /* return on success */ + b safe_syscall_set_errno_tail + + /* code path when we didn't execute the syscall */ +2: lwz 30, 4(1) + addi 1, 1, 8 + addi 3, 0, QEMU_ERESTARTSYS + b safe_syscall_set_errno_tail + + .cfi_endproc + + .size safe_syscall_base, .-safe_syscall_base
Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- common-user/host/ppc/safe-syscall.inc.S | 107 ++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 common-user/host/ppc/safe-syscall.inc.S