Christoffer Dall <christoffer.d...@linaro.org> writes:

> On Tue, Nov 25, 2014 at 04:10:04PM +0000, Alex Bennée wrote:
>> This is a pre-cursor to sharing the code with the guest debug support.
>> This replaces the big macro that fishes data out of a fixed location
>> with a more general helper macro to restore a set of debug registers. It
>> uses macro substitution so it can be re-used for debug control and value
>> registers. It does however rely on the debug registers being 64 bit
>> aligned (as they happen to be in the hyp ABI).
>
> can you enforce that somewhere?

There is a comment in kvm_asm.h:

/*
 * 0 is reserved as an invalid value.
 * Order *must* be kept in sync with the hyp switch code.
 */

But I'm not sure how to enforce it in assembly. Is there a #pragma or
something I can use?

>
>> 
>> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
>> 
>> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
>> index c0bc218..b38ce3d 100644
>> --- a/arch/arm64/kvm/hyp.S
>> +++ b/arch/arm64/kvm/hyp.S
>> @@ -490,65 +490,12 @@
>>      msr     mdscr_el1,      x25
>>  .endm
>>  
>> -.macro restore_debug
>> -    // x2: base address for cpu context
>> -    // x3: tmp register
>> -
>> -    mrs     x26, id_aa64dfr0_el1
>> -    ubfx    x24, x26, #12, #4       // Extract BRPs
>> -    ubfx    x25, x26, #20, #4       // Extract WRPs
>> -    mov     w26, #15
>> -    sub     w24, w26, w24           // How many BPs to skip
>> -    sub     w25, w26, w25           // How many WPs to skip
>> -
>> -    add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x24, lsl #2
>> -    br      x26
>> -1:
>> -    ldr     x20, [x3, #(15 * 8)]
>> -    ldr     x19, [x3, #(14 * 8)]
>> -    ldr     x18, [x3, #(13 * 8)]
>> -    ldr     x17, [x3, #(12 * 8)]
>> -    ldr     x16, [x3, #(11 * 8)]
>> -    ldr     x15, [x3, #(10 * 8)]
>> -    ldr     x14, [x3, #(9 * 8)]
>> -    ldr     x13, [x3, #(8 * 8)]
>> -    ldr     x12, [x3, #(7 * 8)]
>> -    ldr     x11, [x3, #(6 * 8)]
>> -    ldr     x10, [x3, #(5 * 8)]
>> -    ldr     x9, [x3, #(4 * 8)]
>> -    ldr     x8, [x3, #(3 * 8)]
>> -    ldr     x7, [x3, #(2 * 8)]
>> -    ldr     x6, [x3, #(1 * 8)]
>> -    ldr     x5, [x3, #(0 * 8)]
>> -
>> +.macro setup_debug_registers type
>> +        // x3: pointer to register set
>> +        // x4: number of registers to copy
>> +        // x5..x20/x26 trashed
>
> does this mean x5 through x20, and x26, get trashed or that potentially
> x5 thgough x26 get trashed?  I'm assuming the first, so replace the
> slash with 'and' would be more clear.
>
>>      adr     x26, 1f
>> -    add     x26, x26, x24, lsl #2
>> -    br      x26
>> -1:
>> -    msr     dbgbcr15_el1, x20
>> -    msr     dbgbcr14_el1, x19
>> -    msr     dbgbcr13_el1, x18
>> -    msr     dbgbcr12_el1, x17
>> -    msr     dbgbcr11_el1, x16
>> -    msr     dbgbcr10_el1, x15
>> -    msr     dbgbcr9_el1, x14
>> -    msr     dbgbcr8_el1, x13
>> -    msr     dbgbcr7_el1, x12
>> -    msr     dbgbcr6_el1, x11
>> -    msr     dbgbcr5_el1, x10
>> -    msr     dbgbcr4_el1, x9
>> -    msr     dbgbcr3_el1, x8
>> -    msr     dbgbcr2_el1, x7
>> -    msr     dbgbcr1_el1, x6
>> -    msr     dbgbcr0_el1, x5
>> -
>> -    add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x24, lsl #2
>> +    add     x26, x26, x4, lsl #2
>>      br      x26
>>  1:
>>      ldr     x20, [x3, #(15 * 8)]
>> @@ -569,116 +516,25 @@
>>      ldr     x5, [x3, #(0 * 8)]
>>  
>>      adr     x26, 1f
>> -    add     x26, x26, x24, lsl #2
>> -    br      x26
>> -1:
>> -    msr     dbgbvr15_el1, x20
>> -    msr     dbgbvr14_el1, x19
>> -    msr     dbgbvr13_el1, x18
>> -    msr     dbgbvr12_el1, x17
>> -    msr     dbgbvr11_el1, x16
>> -    msr     dbgbvr10_el1, x15
>> -    msr     dbgbvr9_el1, x14
>> -    msr     dbgbvr8_el1, x13
>> -    msr     dbgbvr7_el1, x12
>> -    msr     dbgbvr6_el1, x11
>> -    msr     dbgbvr5_el1, x10
>> -    msr     dbgbvr4_el1, x9
>> -    msr     dbgbvr3_el1, x8
>> -    msr     dbgbvr2_el1, x7
>> -    msr     dbgbvr1_el1, x6
>> -    msr     dbgbvr0_el1, x5
>> -
>> -    add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x25, lsl #2
>> +    add     x26, x26, x4, lsl #2
>>      br      x26
>>  1:
>> -    ldr     x20, [x3, #(15 * 8)]
>> -    ldr     x19, [x3, #(14 * 8)]
>> -    ldr     x18, [x3, #(13 * 8)]
>> -    ldr     x17, [x3, #(12 * 8)]
>> -    ldr     x16, [x3, #(11 * 8)]
>> -    ldr     x15, [x3, #(10 * 8)]
>> -    ldr     x14, [x3, #(9 * 8)]
>> -    ldr     x13, [x3, #(8 * 8)]
>> -    ldr     x12, [x3, #(7 * 8)]
>> -    ldr     x11, [x3, #(6 * 8)]
>> -    ldr     x10, [x3, #(5 * 8)]
>> -    ldr     x9, [x3, #(4 * 8)]
>> -    ldr     x8, [x3, #(3 * 8)]
>> -    ldr     x7, [x3, #(2 * 8)]
>> -    ldr     x6, [x3, #(1 * 8)]
>> -    ldr     x5, [x3, #(0 * 8)]
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x25, lsl #2
>> -    br      x26
>> -1:
>> -    msr     dbgwcr15_el1, x20
>> -    msr     dbgwcr14_el1, x19
>> -    msr     dbgwcr13_el1, x18
>> -    msr     dbgwcr12_el1, x17
>> -    msr     dbgwcr11_el1, x16
>> -    msr     dbgwcr10_el1, x15
>> -    msr     dbgwcr9_el1, x14
>> -    msr     dbgwcr8_el1, x13
>> -    msr     dbgwcr7_el1, x12
>> -    msr     dbgwcr6_el1, x11
>> -    msr     dbgwcr5_el1, x10
>> -    msr     dbgwcr4_el1, x9
>> -    msr     dbgwcr3_el1, x8
>> -    msr     dbgwcr2_el1, x7
>> -    msr     dbgwcr1_el1, x6
>> -    msr     dbgwcr0_el1, x5
>> -
>> -    add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x25, lsl #2
>> -    br      x26
>> -1:
>> -    ldr     x20, [x3, #(15 * 8)]
>> -    ldr     x19, [x3, #(14 * 8)]
>> -    ldr     x18, [x3, #(13 * 8)]
>> -    ldr     x17, [x3, #(12 * 8)]
>> -    ldr     x16, [x3, #(11 * 8)]
>> -    ldr     x15, [x3, #(10 * 8)]
>> -    ldr     x14, [x3, #(9 * 8)]
>> -    ldr     x13, [x3, #(8 * 8)]
>> -    ldr     x12, [x3, #(7 * 8)]
>> -    ldr     x11, [x3, #(6 * 8)]
>> -    ldr     x10, [x3, #(5 * 8)]
>> -    ldr     x9, [x3, #(4 * 8)]
>> -    ldr     x8, [x3, #(3 * 8)]
>> -    ldr     x7, [x3, #(2 * 8)]
>> -    ldr     x6, [x3, #(1 * 8)]
>> -    ldr     x5, [x3, #(0 * 8)]
>> -
>> -    adr     x26, 1f
>> -    add     x26, x26, x25, lsl #2
>> -    br      x26
>> -1:
>> -    msr     dbgwvr15_el1, x20
>> -    msr     dbgwvr14_el1, x19
>> -    msr     dbgwvr13_el1, x18
>> -    msr     dbgwvr12_el1, x17
>> -    msr     dbgwvr11_el1, x16
>> -    msr     dbgwvr10_el1, x15
>> -    msr     dbgwvr9_el1, x14
>> -    msr     dbgwvr8_el1, x13
>> -    msr     dbgwvr7_el1, x12
>> -    msr     dbgwvr6_el1, x11
>> -    msr     dbgwvr5_el1, x10
>> -    msr     dbgwvr4_el1, x9
>> -    msr     dbgwvr3_el1, x8
>> -    msr     dbgwvr2_el1, x7
>> -    msr     dbgwvr1_el1, x6
>> -    msr     dbgwvr0_el1, x5
>> -
>> -    ldr     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
>> -    msr     mdccint_el1, x21
>> +    msr     \type\()15_el1, x20
>> +    msr     \type\()14_el1, x19
>> +    msr     \type\()13_el1, x18
>> +    msr     \type\()12_el1, x17
>> +    msr     \type\()11_el1, x16
>> +    msr     \type\()10_el1, x15
>> +    msr     \type\()9_el1, x14
>> +    msr     \type\()8_el1, x13
>> +    msr     \type\()7_el1, x12
>> +    msr     \type\()6_el1, x11
>> +    msr     \type\()5_el1, x10
>> +    msr     \type\()4_el1, x9
>> +    msr     \type\()3_el1, x8
>> +    msr     \type\()2_el1, x7
>> +    msr     \type\()1_el1, x6
>> +    msr     \type\()0_el1, x5
>>  .endm
>>  
>>  .macro skip_32bit_state tmp, target
>> @@ -929,8 +785,34 @@ __save_debug:
>>      save_debug
>>      ret
>>  
>> +/* Restore saved guest debug state */
>>  __restore_debug:
>> -    restore_debug
>> +    // x2: base address for cpu context
>> +    // x3: ptr to guest registers passed to setup_debug_registers
>> +    // x5..x20/x26: trashed
>> +
>> +    mrs     x26, id_aa64dfr0_el1
>> +    ubfx    x24, x26, #12, #4       // Extract BRPs
>> +    ubfx    x25, x26, #20, #4       // Extract WRPs
>> +    mov     w26, #15
>> +    sub     w24, w26, w24           // How many BPs to skip
>> +    sub     w25, w26, w25           // How many WPs to skip
>> +
>> +    mov     x4, x24
>> +    add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
>> +    setup_debug_registers dbgbcr
>> +    add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
>> +    setup_debug_registers dbgbvr
>> +
>> +    mov     x4, x25
>> +    add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
>> +    setup_debug_registers dbgwcr
>> +    add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
>> +    setup_debug_registers dbgwvr
>> +
>> +    ldr     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
>> +    msr     mdccint_el1, x21
>> +
>>      ret
>>  
>>  __save_fpsimd:
>> -- 
>> 2.1.3
>> 

-- 
Alex Bennée
--
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