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Date: Mon, 01 Dec 2014 11:52:44 +0000 From: Alex Bennée <alex.bennee@...aro.org> To: Christoffer Dall <christoffer.dall@...aro.org> Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu, marc.zyngier@....com, peter.maydell@...aro.org, agraf@...e.de, jan.kiszka@...mens.com, dahi@...ux.vnet.ibm.com, r65777@...escale.com, bp@...e.de, pbonzini@...hat.com, Gleb Natapov <gleb@...nel.org>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, open list <linux-kernel@...r.kernel.org> Subject: Re: [PATCH 6/7] KVM: arm64: re-factor hyp.S debug register code Christoffer Dall <christoffer.dall@...aro.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.bennee@...aro.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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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