| Message ID | 20210421190207.1803139-7-amanieu@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Allow 64-bit tasks to invoke compat syscalls | expand |
From: Amanieu d'Antras > Sent: 21 April 2021 20:02 > > This flag is used by in_compat_syscall to handle compat syscalls coming > from 64-bit tasks. > > Signed-off-by: Amanieu d'Antras <amanieu@gmail.com> > Co-developed-by: Ryan Houdek <Houdek.Ryan@fex-emu.org> > Signed-off-by: Ryan Houdek <Houdek.Ryan@fex-emu.org> > --- > arch/arm64/include/asm/compat.h | 5 +++-- > arch/arm64/include/asm/elf.h | 13 ++++++++++++- > arch/arm64/include/asm/thread_info.h | 3 +++ > 3 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h > index a2f5001f7793..71de0ba8b160 100644 > --- a/arch/arm64/include/asm/compat.h > +++ b/arch/arm64/include/asm/compat.h > @@ -190,13 +190,14 @@ static inline bool is_compat_thread(struct thread_info *thread) > > static inline bool in_compat_syscall(void) > { > - return is_compat_task(); > + return is_compat_task() || > + current_thread_info()->aarch64_compat_syscall; > } ... Wouldn't it be better to ensure that a 'compat_task' always has aarch64_compat_syscall set. If you can't do that, just replacing the '||' with '|' will generate better code for the usual case of both flags being clear. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
> Wouldn't it be better to ensure that a 'compat_task' > always has aarch64_compat_syscall set. Good point, I'll do that in the next version of the patch.
diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h index a2f5001f7793..71de0ba8b160 100644 --- a/arch/arm64/include/asm/compat.h +++ b/arch/arm64/include/asm/compat.h @@ -190,13 +190,14 @@ static inline bool is_compat_thread(struct thread_info *thread) static inline bool in_compat_syscall(void) { - return is_compat_task(); + return is_compat_task() || + current_thread_info()->aarch64_compat_syscall; } #define in_compat_syscall in_compat_syscall /* override the generic impl */ static inline bool thread_in_compat_syscall(struct thread_info *thread) { - return is_compat_thread(thread); + return is_compat_thread(thread) || thread->aarch64_compat_syscall; } #else /* !CONFIG_COMPAT */ diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index e21964898d06..f4f4ffe37ee5 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -158,10 +158,20 @@ typedef struct user_fpsimd_state elf_fpregset_t; */ #define ELF_PLAT_INIT(_r, load_addr) (_r)->regs[0] = 0 +#ifdef CONFIG_COMPAT +#define CLEAR_AARCH64_COMPAT_SYSCALL() \ +({ \ + current_thread_info()->aarch64_compat_syscall = false; \ +}) +#else +#define CLEAR_AARCH64_COMPAT_SYSCALL() ((void)0) +#endif + #define SET_PERSONALITY(ex) \ ({ \ clear_thread_flag(TIF_32BIT); \ current->personality &= ~READ_IMPLIES_EXEC; \ + CLEAR_AARCH64_COMPAT_SYSCALL(); \ }) /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */ @@ -228,7 +238,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; #define COMPAT_SET_PERSONALITY(ex) \ ({ \ set_thread_flag(TIF_32BIT); \ - }) + CLEAR_AARCH64_COMPAT_SYSCALL(); \ +}) #ifdef CONFIG_COMPAT_VDSO #define COMPAT_ARCH_DLINFO \ do { \ diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 6623c99f0984..756e977fc37a 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -42,6 +42,9 @@ struct thread_info { void *scs_base; void *scs_sp; #endif +#ifdef CONFIG_COMPAT + bool aarch64_compat_syscall; +#endif }; #define thread_saved_pc(tsk) \