[Barrelfish-users] Make armv7 cpu driver run in SVC mode

[Wang Nan]

于 2013/7/15 16:52, Wang Nan 写道:
> Hi,
> 
> As I mentioned early, I provide a patch on armv7, which makes cpu driver executes on ARMv7 platform, and fixes
> the cpsr clobber problem.
> 

What I mean is making cpu driver to execute at SVC mode. Sorry.

> For all arm platform:
> 
> diff --git a/kernel/arch/arm/exec.c b/kernel/arch/arm/exec.c
> index e73e437..fdeb1ed 100644
> --- a/kernel/arch/arm/exec.c
> +++ b/kernel/arch/arm/exec.c
> @@ -63,7 +63,11 @@ void do_resume(uint32_t *regs)
>          /* "ldmia  lr!, {r13}                              \n\t" */
>          /* // Restore LR and PC */
>          /* "ldmia  lr!, {r14-r15}                          \n\t" */
> -        "ldmia  %[regs], {r0-r15}^                          \n\t"
> +	"mov lr, %[regs]\n\t"
> +	"ldmia lr, {r0 - lr}^\n\t"
> +	"add lr, #4*15\n\t"
> +	"ldr lr, [lr]\n\t"
> +	"movs pc, lr\n\t"
>          // Make sure pipeline is clear
>          "nop                          \n\t"
>          "nop                          \n\t"
> @@ -148,7 +152,7 @@ void wait_for_interrupt(void)
>      // Switch to priviledged mode with interrupts enabled.
>      __asm volatile(
>          //"mov    r0, #" XTR(ARM_MODE_SYS) "              \n\t"
> -        "mov    r0, #" XTR(ARM_MODE_PRIV) "              \n\t"
> +        "mov    r0, #" XTR(ARM_MODE_SVC) "              \n\t"
>          "msr    cpsr_c, r0                              \n\t"
>          "0:                                             \n\t"
>  #if defined(__ARM_ARCH_6K__)
> diff --git a/kernel/arch/armv7/exceptions.S b/kernel/arch/armv7/exceptions.S
> index 14e20af..e8e403a 100644
> --- a/kernel/arch/armv7/exceptions.S
> +++ b/kernel/arch/armv7/exceptions.S
> @@ -57,11 +57,6 @@ undef_stack:
>  undef_stack_top:
>          .space 8, 0
> 
> -svc_stack:
> -        .space EXCEPTION_MODE_STACK_BYTES, 0
> -svc_stack_top:
> -        .space 8, 0
> -
>          //
>          // System mode stack
>          //
> @@ -112,9 +107,6 @@ $exceptions_load_stacks:
>          mov     r0, # ARM_MODE_UND
>          ldr     r1, = undef_stack_top
>          bl      set_stack_for_mode
> -        mov     r0, # ARM_MODE_SVC
> -        ldr     r1, = svc_stack_top
> -        bl      set_stack_for_mode
>  $exceptions_install_handlers:
>          mov     r0, # ARM_EVECTOR_PABT
>          adr     r1, pabt_handler
> @@ -262,7 +254,7 @@ null_handler:
>          //
>  .macro enter_sys scratch
>  	clrex
> -        mov \scratch, #(CPSR_IF_MASK | ARM_MODE_SYS)
> +        mov \scratch, #(CPSR_IF_MASK | ARM_MODE_SVC)
>          msr cpsr_c, \scratch
>          init_sys_pic_register
>          init_sys_stack
> 
> 
> 
> Omap specific code (I don't have pandaboard platform, so following code has not been tested yet)
> 
> --- a/kernel/arch/???/boot.S
> +++ b/kernel/arch/???/boot.S
> @@ -24,7 +24,7 @@ start:
>          //
>          mrs     r3, cpsr
>          bic     r3, r3, #ARM_MODE_MASK
> -        orr     r3, r3, #ARM_MODE_PRIV  // Ensure in privileged mode
> +        orr     r3, r3, #ARM_MODE_SVC  // Ensure in privileged mode
>          msr     cpsr_c, r3		// _c => don't change cond. codes
> 
> 
> 
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