>Le 12/10/2024 à 05:56, Luming Yu a écrit : >> convert powerpc entry code in syscall and fault to use syscall_work >> and irqentry_state as well as common calls implemented in generic >> entry infrastructure. >> >> Signed-off-by: Luming Yu <luming...@shingroup.cn> >> --- >> arch/powerpc/Kconfig | 1 + >> arch/powerpc/include/asm/hw_irq.h | 5 +++++ >> arch/powerpc/include/asm/processor.h | 6 ++++++ >> arch/powerpc/include/asm/syscall.h | 5 +++++ >> arch/powerpc/include/asm/thread_info.h | 1 + >> arch/powerpc/kernel/syscall.c | 5 ++++- >> arch/powerpc/mm/fault.c | 3 +++ >> 7 files changed, 25 insertions(+), 1 deletion(-) >> > >... > >> diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c >> index 77fedb190c93..e0338bd8d383 100644 >> --- a/arch/powerpc/kernel/syscall.c >> +++ b/arch/powerpc/kernel/syscall.c >> @@ -3,6 +3,7 @@ >> #include <linux/compat.h> >> #include <linux/context_tracking.h> >> #include <linux/randomize_kstack.h> >> +#include <linux/entry-common.h> >> >> #include <asm/interrupt.h> >> #include <asm/kup.h> >> @@ -131,7 +132,7 @@ notrace long system_call_exception(struct pt_regs *regs, >> unsigned long r0) >> * and the test against NR_syscalls will fail and the return >> * value to be used is in regs->gpr[3]. >> */ >> - r0 = do_syscall_trace_enter(regs); >> + r0 = syscall_enter_from_user_mode(regs, r0); > >Can you provide details on how this works ? I assume the common entry would take over th details. So I just made the switch from the high level call.
As you said as the subtle ABI requirement about regs->r3 needs to be restored, I'm wondering which test can capture the lost ABI feature. As simple Boot test is insufficient, what is the test set that can capture it? I will look into the details late this week. > >For instance, do_syscall_trace_enter() was calling do_seccomp(). >do_seccomp() sets regs->r3 to -ENOSYS then calls __secure_computing(). > >Now you call syscall_enter_from_user_mode() instead which calls >syscall_enter_from_user_mode_work() which calls syscall_trace_enter() >which calls __secure_computing() but without seting regs->r3 to -ENOSYS. > >So what will be returned by the below return when >syscall_enter_from_user_mode returns -1 ? > >> if (unlikely(r0 >= NR_syscalls)) >> return regs->gpr[3]; >> >> @@ -184,6 +185,8 @@ notrace long system_call_exception(struct pt_regs *regs, >> unsigned long r0) >> * So the resulting 6 or 7 bits of entropy is seen in SP[9:4] or >> SP[9:3]. >> */ >> choose_random_kstack_offset(mftb()); >> + /*common entry*/ >> + syscall_exit_to_user_mode(regs); >> >> return ret; >> }
