Messages in this thread Patch in this message | | | Date | Thu, 28 Nov 2019 16:36:44 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH] ptrace/x86: introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall() |
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On 11/27, Linus Torvalds wrote: > > On Wed, Nov 27, 2019 at 9:02 AM Oleg Nesterov <oleg@redhat.com> wrote: > > > > OK, lets add the new restart_block.nr_restart_syscall field, then we need > > > > void set_restart_block_fn(restart, fn) > > { > > restart->nr_restart_syscall = arch_get_nr_restart_syscall() > > restart->fn = fn; > > } > > No, I'd suggest just adding an arch-specific "unsigned long" to the > restart data (and not force the naming to something like the system > call number - that's just an x86 detail), and then something like this > on x86: > > void arch_set_restart_data(restart) > { > restart->arch_data = x86_get_restart_syscall(); > } > #define arch_set_restart_data arch_set_restart_data > > and then we'd have in generic code something like > > #ifndef arch_set_restart_data > #define arch_set_restart_data(block) do { } while (0) > #endif
OK, let it be arch_data/arch_set_restart_data, the same thing.
You misunderstood my question, I do not see a good place for the code above. So I am going to uglify */signal.[ch] files.
See the incomplete patch below, everything else is trivial.
Please tell me if you think I should move this code somewhere else.
Oleg.
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h index 33d3c88..f536bcb 100644 --- a/arch/x86/include/asm/signal.h +++ b/arch/x86/include/asm/signal.h @@ -5,6 +5,10 @@ #ifndef __ASSEMBLY__ #include <linux/linkage.h> +struct restart_block; +extern void arch_set_restart_data(struct restart_block *); +#define arch_set_restart_data arch_set_restart_data + /* Most things should be clean enough to redefine this at will, if care is taken to make libc match. */ diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 8eb7193..ede5443 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -768,6 +768,11 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) signal_setup_done(failed, ksig, stepping); } +void arch_set_restart_data(struct restart_block *restart) +{ + // TODO +} + static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) { /* diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h index bba2920..d39f836 100644 --- a/include/linux/restart_block.h +++ b/include/linux/restart_block.h @@ -55,6 +55,8 @@ struct restart_block { }; }; +extern long set_restart_fn(struct restart_block *restart, + long (*fn)(struct restart_block *)); extern long do_no_restart_syscall(struct restart_block *parm); #endif /* __LINUX_RESTART_BLOCK_H */ diff --git a/include/linux/signal.h b/include/linux/signal.h index 1a5f883..542499f 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -5,12 +5,17 @@ #include <linux/bug.h> #include <linux/signal_types.h> #include <linux/string.h> +#include <linux/restart_block.h> struct task_struct; /* for sysctl */ extern int print_fatal_signals; +#ifndef arch_set_restart_data +#define arch_set_restart_data(restart) do { } while (0) +#endif + static inline void copy_siginfo(kernel_siginfo_t *to, const kernel_siginfo_t *from) { diff --git a/kernel/signal.c b/kernel/signal.c index bcd46f5..d6402e6 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -4493,6 +4493,14 @@ SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask) } #endif +long set_restart_fn(struct restart_block *restart, + long (*fn)(struct restart_block *)) +{ + restart->fn = fn; + arch_set_restart_data(restart); + return -ERESTART_RESTARTBLOCK; +} + __weak const char *arch_vma_name(struct vm_area_struct *vma) { return NULL;
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