[PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
Implement specific usage of verify_pre_usermode_state for user-mode returns for arm. --- Based on next-20170308 --- arch/arm/Kconfig | 1 + arch/arm/kernel/entry-common.S | 5 + 2 files changed, 6 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 0d4e71b42c77..704fd8f197fa 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -12,6 +12,7 @@ config ARM select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_MIGHT_HAVE_PC_PARPORT + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 select ARCH_SUPPORTS_ATOMIC_RMW diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index eb5cd77bf1d8..80cfdc7fabde 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -39,6 +39,9 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind) + push{r0}@ save returned r0 + bl verify_pre_usermode_state + pop {r0}@ restore r0 disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -65,6 +68,7 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind) str r0, [sp, #S_R0 + S_OFF]!@ save returned r0 + bl verify_pre_usermode_state disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -263,6 +267,7 @@ __sys_trace: __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]!@ save returned r0 + bl verify_pre_usermode_state mov r0, sp bl syscall_trace_exit b ret_slow_syscall -- 2.12.0.246.ga2ecc84866-goog
[PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
Implement specific usage of verify_pre_usermode_state for user-mode returns for arm. --- Based on next-20170308 --- arch/arm/Kconfig | 1 + arch/arm/kernel/entry-common.S | 5 + 2 files changed, 6 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 0d4e71b42c77..704fd8f197fa 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -12,6 +12,7 @@ config ARM select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_MIGHT_HAVE_PC_PARPORT + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 select ARCH_SUPPORTS_ATOMIC_RMW diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index eb5cd77bf1d8..80cfdc7fabde 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -39,6 +39,9 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind) + push{r0}@ save returned r0 + bl verify_pre_usermode_state + pop {r0}@ restore r0 disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -65,6 +68,7 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind) str r0, [sp, #S_R0 + S_OFF]!@ save returned r0 + bl verify_pre_usermode_state disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -263,6 +267,7 @@ __sys_trace: __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]!@ save returned r0 + bl verify_pre_usermode_state mov r0, sp bl syscall_trace_exit b ret_slow_syscall -- 2.12.0.246.ga2ecc84866-goog
Re: [PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
On Wed, 8 Mar 2017, Thomas Garnier wrote: > Implement specific usage of verify_pre_usermode_state for user-mode > returns for arm. > --- > Based on next-20170308 > --- > arch/arm/Kconfig | 1 + > arch/arm/kernel/entry-common.S | 5 + > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 0d4e71b42c77..704fd8f197fa 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -12,6 +12,7 @@ config ARM > select ARCH_HAVE_CUSTOM_GPIO_H > select ARCH_HAS_GCOV_PROFILE_ALL > select ARCH_MIGHT_HAVE_PC_PARPORT > + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE > select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX > select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 > select ARCH_SUPPORTS_ATOMIC_RMW > diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S > index eb5cd77bf1d8..80cfdc7fabde 100644 > --- a/arch/arm/kernel/entry-common.S > +++ b/arch/arm/kernel/entry-common.S > @@ -39,6 +39,9 @@ > ret_fast_syscall: > UNWIND(.fnstart ) > UNWIND(.cantunwind ) > + push{r0}@ save returned r0 > + bl verify_pre_usermode_state > + pop {r0}@ restore r0 > disable_irq_notrace @ disable interrupts > ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing > tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK This feature is configurable, right? Here the branch overhead is imposed even if the feature is configured out. You should consider conditionally defining a macro like some other features do. Furthermore I think we still support old toolchains that don't know what push and pop mean. You should use the legacy syntax instead. Nicolas
Re: [PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
On Wed, 8 Mar 2017, Thomas Garnier wrote: > Implement specific usage of verify_pre_usermode_state for user-mode > returns for arm. > --- > Based on next-20170308 > --- > arch/arm/Kconfig | 1 + > arch/arm/kernel/entry-common.S | 5 + > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 0d4e71b42c77..704fd8f197fa 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -12,6 +12,7 @@ config ARM > select ARCH_HAVE_CUSTOM_GPIO_H > select ARCH_HAS_GCOV_PROFILE_ALL > select ARCH_MIGHT_HAVE_PC_PARPORT > + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE > select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX > select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 > select ARCH_SUPPORTS_ATOMIC_RMW > diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S > index eb5cd77bf1d8..80cfdc7fabde 100644 > --- a/arch/arm/kernel/entry-common.S > +++ b/arch/arm/kernel/entry-common.S > @@ -39,6 +39,9 @@ > ret_fast_syscall: > UNWIND(.fnstart ) > UNWIND(.cantunwind ) > + push{r0}@ save returned r0 > + bl verify_pre_usermode_state > + pop {r0}@ restore r0 > disable_irq_notrace @ disable interrupts > ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing > tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK This feature is configurable, right? Here the branch overhead is imposed even if the feature is configured out. You should consider conditionally defining a macro like some other features do. Furthermore I think we still support old toolchains that don't know what push and pop mean. You should use the legacy syntax instead. Nicolas
Re: [PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
On Wed, Mar 08, 2017 at 01:38:43PM -0800, Thomas Garnier wrote: > Implement specific usage of verify_pre_usermode_state for user-mode > returns for arm. > --- > Based on next-20170308 > --- > arch/arm/Kconfig | 1 + > arch/arm/kernel/entry-common.S | 5 + > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 0d4e71b42c77..704fd8f197fa 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -12,6 +12,7 @@ config ARM > select ARCH_HAVE_CUSTOM_GPIO_H > select ARCH_HAS_GCOV_PROFILE_ALL > select ARCH_MIGHT_HAVE_PC_PARPORT > + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE > select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX > select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 > select ARCH_SUPPORTS_ATOMIC_RMW > diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S > index eb5cd77bf1d8..80cfdc7fabde 100644 > --- a/arch/arm/kernel/entry-common.S > +++ b/arch/arm/kernel/entry-common.S > @@ -39,6 +39,9 @@ > ret_fast_syscall: > UNWIND(.fnstart ) > UNWIND(.cantunwind ) > + push{r0}@ save returned r0 > + bl verify_pre_usermode_state > + pop {r0}@ restore r0 This really makes the fast exit utterly pointless, and we might as well rip all that out. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
Re: [PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state
On Wed, Mar 08, 2017 at 01:38:43PM -0800, Thomas Garnier wrote: > Implement specific usage of verify_pre_usermode_state for user-mode > returns for arm. > --- > Based on next-20170308 > --- > arch/arm/Kconfig | 1 + > arch/arm/kernel/entry-common.S | 5 + > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 0d4e71b42c77..704fd8f197fa 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -12,6 +12,7 @@ config ARM > select ARCH_HAVE_CUSTOM_GPIO_H > select ARCH_HAS_GCOV_PROFILE_ALL > select ARCH_MIGHT_HAVE_PC_PARPORT > + select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE > select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX > select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7 > select ARCH_SUPPORTS_ATOMIC_RMW > diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S > index eb5cd77bf1d8..80cfdc7fabde 100644 > --- a/arch/arm/kernel/entry-common.S > +++ b/arch/arm/kernel/entry-common.S > @@ -39,6 +39,9 @@ > ret_fast_syscall: > UNWIND(.fnstart ) > UNWIND(.cantunwind ) > + push{r0}@ save returned r0 > + bl verify_pre_usermode_state > + pop {r0}@ restore r0 This really makes the fast exit utterly pointless, and we might as well rip all that out. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.