Re: [PATCH v6 3/4] ARM: Move some macros from entry-armv to entry-header

From: Nicolas Pitre
Date: Tue Jun 24 2014 - 11:54:03 EST

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On Tue, 24 Jun 2014, Daniel Thompson wrote:

> From: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
>
> Just move the macros into header file as we would want to use them for
> KGDB FIQ entry code.
>
> The following macros were moved:
>
> - svc_entry
> - usr_entry
> - kuser_cmpxchg_check
> - vector_stub
>
> To make kuser_cmpxchg_check actually work across different files, we
> also have to make kuser_cmpxchg64_fixup global.
>
> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> Signed-off-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> Cc: Nicolas Pitre <nico@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>

Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>

> ---
> arch/arm/kernel/entry-armv.S | 151 +------------------------------------
> arch/arm/kernel/entry-header.S | 164 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 165 insertions(+), 150 deletions(-)
>
> diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
> index 52a949a..4172cd6 100644
> --- a/arch/arm/kernel/entry-armv.S
> +++ b/arch/arm/kernel/entry-armv.S
> @@ -140,53 +140,6 @@ ENDPROC(__und_invalid)
> * SVC mode handlers
> */
>
> -#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
> -#define SPFIX(code...) code
> -#else
> -#define SPFIX(code...)
> -#endif
> -
> - .macro svc_entry, stack_hole=0
> - UNWIND(.fnstart )
> - UNWIND(.save {r0 - pc} )
> - sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4)
> -#ifdef CONFIG_THUMB2_KERNEL
> - SPFIX( str r0, [sp] ) @ temporarily saved
> - SPFIX( mov r0, sp )
> - SPFIX( tst r0, #4 ) @ test original stack alignment
> - SPFIX( ldr r0, [sp] ) @ restored
> -#else
> - SPFIX( tst sp, #4 )
> -#endif
> - SPFIX( subeq sp, sp, #4 )
> - stmia sp, {r1 - r12}
> -
> - ldmia r0, {r3 - r5}
> - add r7, sp, #S_SP - 4 @ here for interlock avoidance
> - mov r6, #-1 @ "" "" "" ""
> - add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4)
> - SPFIX( addeq r2, r2, #4 )
> - str r3, [sp, #-4]! @ save the "real" r0 copied
> - @ from the exception stack
> -
> - mov r3, lr
> -
> - @
> - @ We are now ready to fill in the remaining blanks on the stack:
> - @
> - @ r2 - sp_svc
> - @ r3 - lr_svc
> - @ r4 - lr_<exception>, already fixed up for correct return/restart
> - @ r5 - spsr_<exception>
> - @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
> - @
> - stmia r7, {r2 - r6}
> -
> -#ifdef CONFIG_TRACE_IRQFLAGS
> - bl trace_hardirqs_off
> -#endif
> - .endm
> -
> .align 5
> __dabt_svc:
> svc_entry
> @@ -306,73 +259,8 @@ ENDPROC(__pabt_svc)
>
> /*
> * User mode handlers
> - *
> - * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
> */
>
> -#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7)
> -#error "sizeof(struct pt_regs) must be a multiple of 8"
> -#endif
> -
> - .macro usr_entry
> - UNWIND(.fnstart )
> - UNWIND(.cantunwind ) @ don't unwind the user space
> - sub sp, sp, #S_FRAME_SIZE
> - ARM( stmib sp, {r1 - r12} )
> - THUMB( stmia sp, {r0 - r12} )
> -
> - ldmia r0, {r3 - r5}
> - add r0, sp, #S_PC @ here for interlock avoidance
> - mov r6, #-1 @ "" "" "" ""
> -
> - str r3, [sp] @ save the "real" r0 copied
> - @ from the exception stack
> -
> - @
> - @ We are now ready to fill in the remaining blanks on the stack:
> - @
> - @ r4 - lr_<exception>, already fixed up for correct return/restart
> - @ r5 - spsr_<exception>
> - @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
> - @
> - @ Also, separately save sp_usr and lr_usr
> - @
> - stmia r0, {r4 - r6}
> - ARM( stmdb r0, {sp, lr}^ )
> - THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
> -
> - @
> - @ Enable the alignment trap while in kernel mode
> - @
> - alignment_trap r0, .LCcralign
> -
> - @
> - @ Clear FP to mark the first stack frame
> - @
> - zero_fp
> -
> -#ifdef CONFIG_IRQSOFF_TRACER
> - bl trace_hardirqs_off
> -#endif
> - ct_user_exit save = 0
> - .endm
> -
> - .macro kuser_cmpxchg_check
> -#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \
> - !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
> -#ifndef CONFIG_MMU
> -#warning "NPTL on non MMU needs fixing"
> -#else
> - @ Make sure our user space atomic helper is restarted
> - @ if it was interrupted in a critical region. Here we
> - @ perform a quick test inline since it should be false
> - @ 99.9999% of the time. The rest is done out of line.
> - cmp r4, #TASK_SIZE
> - blhs kuser_cmpxchg64_fixup
> -#endif
> -#endif
> - .endm
> -
> .align 5
> __dabt_usr:
> usr_entry
> @@ -823,6 +711,7 @@ __kuser_cmpxchg64: @ 0xffff0f60
> ldmfd sp!, {r4, r5, r6, pc}
>
> .text
> + .global kuser_cmpxchg64_fixup
> kuser_cmpxchg64_fixup:
> @ Called from kuser_cmpxchg_fixup.
> @ r4 = address of interrupted insn (must be preserved).
> @@ -964,44 +853,6 @@ __kuser_helper_end:
> * SP points to a minimal amount of processor-private memory, the address
> * of which is copied into r0 for the mode specific abort handler.
> */
> - .macro vector_stub, name, mode, correction=0
> - .align 5
> -
> -vector_\name:
> - .if \correction
> - sub lr, lr, #\correction
> - .endif
> -
> - @
> - @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
> - @ (parent CPSR)
> - @
> - stmia sp, {r0, lr} @ save r0, lr
> - mrs lr, spsr
> - str lr, [sp, #8] @ save spsr
> -
> - @
> - @ Prepare for SVC32 mode. IRQs remain disabled.
> - @
> - mrs r0, cpsr
> - eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
> - msr spsr_cxsf, r0
> -
> - @
> - @ the branch table must immediately follow this code
> - @
> - and lr, lr, #0x0f
> - THUMB( adr r0, 1f )
> - THUMB( ldr lr, [r0, lr, lsl #2] )
> - mov r0, sp
> - ARM( ldr lr, [pc, lr, lsl #2] )
> - movs pc, lr @ branch to handler in SVC mode
> -ENDPROC(vector_\name)
> -
> - .align 2
> - @ handler addresses follow this label
> -1:
> - .endm
>
> .section .stubs, "ax", %progbits
> __stubs_start:
> diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
> index 5d702f8..eb2c426 100644
> --- a/arch/arm/kernel/entry-header.S
> +++ b/arch/arm/kernel/entry-header.S
> @@ -356,3 +356,167 @@ scno .req r7 @ syscall number
> tbl .req r8 @ syscall table pointer
> why .req r8 @ Linux syscall (!= 0)
> tsk .req r9 @ current thread_info
> +
> +/*
> + * SVC mode handler macros
> + */
> +
> +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
> +#define SPFIX(code...) code
> +#else
> +#define SPFIX(code...)
> +#endif
> +
> + .macro svc_entry, stack_hole=0
> + UNWIND(.fnstart )
> + UNWIND(.save {r0 - pc} )
> + sub sp, sp, #(S_FRAME_SIZE + \stack_hole - 4)
> +#ifdef CONFIG_THUMB2_KERNEL
> + SPFIX( str r0, [sp] ) @ temporarily saved
> + SPFIX( mov r0, sp )
> + SPFIX( tst r0, #4 ) @ test original stack alignment
> + SPFIX( ldr r0, [sp] ) @ restored
> +#else
> + SPFIX( tst sp, #4 )
> +#endif
> + SPFIX( subeq sp, sp, #4 )
> + stmia sp, {r1 - r12}
> +
> + ldmia r0, {r3 - r5}
> + add r7, sp, #S_SP - 4 @ here for interlock avoidance
> + mov r6, #-1 @ "" "" "" ""
> + add r2, sp, #(S_FRAME_SIZE + \stack_hole - 4)
> + SPFIX( addeq r2, r2, #4 )
> + str r3, [sp, #-4]! @ save the "real" r0 copied
> + @ from the exception stack
> +
> + mov r3, lr
> +
> + @
> + @ We are now ready to fill in the remaining blanks on the stack:
> + @
> + @ r2 - sp_svc
> + @ r3 - lr_svc
> + @ r4 - lr_<exception>, already fixed up for correct return/restart
> + @ r5 - spsr_<exception>
> + @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
> + @
> + stmia r7, {r2 - r6}
> +
> +#ifdef CONFIG_TRACE_IRQFLAGS
> + bl trace_hardirqs_off
> +#endif
> + .endm
> +
> +/*
> + * User mode handler macros
> + *
> + * EABI note: sp_svc is always 64-bit aligned here, so should S_FRAME_SIZE
> + */
> +
> +#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) && (S_FRAME_SIZE & 7)
> +#error "sizeof(struct pt_regs) must be a multiple of 8"
> +#endif
> +
> + .macro usr_entry
> + UNWIND(.fnstart )
> + UNWIND(.cantunwind ) @ don't unwind the user space
> + sub sp, sp, #S_FRAME_SIZE
> + ARM( stmib sp, {r1 - r12} )
> + THUMB( stmia sp, {r0 - r12} )
> +
> + ldmia r0, {r3 - r5}
> + add r0, sp, #S_PC @ here for interlock avoidance
> + mov r6, #-1 @ "" "" "" ""
> +
> + str r3, [sp] @ save the "real" r0 copied
> + @ from the exception stack
> +
> + @
> + @ We are now ready to fill in the remaining blanks on the stack:
> + @
> + @ r4 - lr_<exception>, already fixed up for correct return/restart
> + @ r5 - spsr_<exception>
> + @ r6 - orig_r0 (see pt_regs definition in ptrace.h)
> + @
> + @ Also, separately save sp_usr and lr_usr
> + @
> + stmia r0, {r4 - r6}
> + ARM( stmdb r0, {sp, lr}^ )
> + THUMB( store_user_sp_lr r0, r1, S_SP - S_PC )
> +
> + @
> + @ Enable the alignment trap while in kernel mode
> + @
> + alignment_trap r0, .LCcralign
> +
> + @
> + @ Clear FP to mark the first stack frame
> + @
> + zero_fp
> +
> +#ifdef CONFIG_IRQSOFF_TRACER
> + bl trace_hardirqs_off
> +#endif
> + ct_user_exit save = 0
> + .endm
> +
> + .macro kuser_cmpxchg_check
> +#if !defined(CONFIG_CPU_32v6K) && defined(CONFIG_KUSER_HELPERS) && \
> + !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
> +#ifndef CONFIG_MMU
> +#warning "NPTL on non MMU needs fixing"
> +#else
> + @ Make sure our user space atomic helper is restarted
> + @ if it was interrupted in a critical region. Here we
> + @ perform a quick test inline since it should be false
> + @ 99.9999% of the time. The rest is done out of line.
> + cmp r4, #TASK_SIZE
> + blhs kuser_cmpxchg64_fixup
> +#endif
> +#endif
> + .endm
> +
> +/*
> + * Vector stubs macro.
> + */
> + .macro vector_stub, name, mode, correction=0
> + .align 5
> +
> +vector_\name:
> + .if \correction
> + sub lr, lr, #\correction
> + .endif
> +
> + @
> + @ Save r0, lr_<exception> (parent PC) and spsr_<exception>
> + @ (parent CPSR)
> + @
> + stmia sp, {r0, lr} @ save r0, lr
> + mrs lr, spsr
> + str lr, [sp, #8] @ save spsr
> +
> + @
> + @ Prepare for SVC32 mode. IRQs remain disabled.
> + @
> + mrs r0, cpsr
> + eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
> + msr spsr_cxsf, r0
> +
> + @
> + @ the branch table must immediately follow this code
> + @
> + and lr, lr, #0x0f
> + THUMB( adr r0, 1f )
> + THUMB( ldr lr, [r0, lr, lsl #2] )
> + mov r0, sp
> + ARM( ldr lr, [pc, lr, lsl #2] )
> + movs pc, lr @ branch to handler in SVC mode
> +ENDPROC(vector_\name)
> +
> + .align 2
> + @ handler addresses follow this label
> +1:
> + .endm
> +
> +
> --
> 1.9.3
>
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Next in thread: Daniel Thompson: "[PATCH v7 0/4] arm: KGDB NMI/FIQ support"
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