2021-01-18 10:14:58

by Marc Zyngier

[permalink] [raw]
Subject: [PATCH v4 01/21] arm64: Fix labels in el2_setup macros

If someone happens to write the following code:

b 1f
init_el2_state vhe
1:
[...]

they will be in for a long debugging session, as the label "1f"
will be resolved *inside* the init_el2_state macro instead of
after it. Not really what one expects.

Instead, rewite the EL2 setup macros to use unambiguous labels,
thanks to the usual macro counter trick.

Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
---
arch/arm64/include/asm/el2_setup.h | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index a7f5a1bbc8ac..540116de80bf 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -45,24 +45,24 @@
mrs x1, id_aa64dfr0_el1
sbfx x0, x1, #ID_AA64DFR0_PMUVER_SHIFT, #4
cmp x0, #1
- b.lt 1f // Skip if no PMU present
+ b.lt .Lskip_pmu_\@ // Skip if no PMU present
mrs x0, pmcr_el0 // Disable debug access traps
ubfx x0, x0, #11, #5 // to EL2 and allow access to
-1:
+.Lskip_pmu_\@:
csel x2, xzr, x0, lt // all PMU counters from EL1

/* Statistical profiling */
ubfx x0, x1, #ID_AA64DFR0_PMSVER_SHIFT, #4
- cbz x0, 3f // Skip if SPE not present
+ cbz x0, .Lskip_spe_\@ // Skip if SPE not present

.ifeqs "\mode", "nvhe"
mrs_s x0, SYS_PMBIDR_EL1 // If SPE available at EL2,
and x0, x0, #(1 << SYS_PMBIDR_EL1_P_SHIFT)
- cbnz x0, 2f // then permit sampling of physical
+ cbnz x0, .Lskip_spe_el2_\@ // then permit sampling of physical
mov x0, #(1 << SYS_PMSCR_EL2_PCT_SHIFT | \
1 << SYS_PMSCR_EL2_PA_SHIFT)
msr_s SYS_PMSCR_EL2, x0 // addresses and physical counter
-2:
+.Lskip_spe_el2_\@:
mov x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
orr x2, x2, x0 // If we don't have VHE, then
// use EL1&0 translation.
@@ -71,7 +71,7 @@
// and disable access from EL1
.endif

-3:
+.Lskip_spe_\@:
msr mdcr_el2, x2 // Configure debug traps
.endm

@@ -79,9 +79,9 @@
.macro __init_el2_lor
mrs x1, id_aa64mmfr1_el1
ubfx x0, x1, #ID_AA64MMFR1_LOR_SHIFT, 4
- cbz x0, 1f
+ cbz x0, .Lskip_lor_\@
msr_s SYS_LORC_EL1, xzr
-1:
+.Lskip_lor_\@:
.endm

/* Stage-2 translation */
@@ -93,7 +93,7 @@
.macro __init_el2_gicv3
mrs x0, id_aa64pfr0_el1
ubfx x0, x0, #ID_AA64PFR0_GIC_SHIFT, #4
- cbz x0, 1f
+ cbz x0, .Lskip_gicv3_\@

mrs_s x0, SYS_ICC_SRE_EL2
orr x0, x0, #ICC_SRE_EL2_SRE // Set ICC_SRE_EL2.SRE==1
@@ -103,7 +103,7 @@
mrs_s x0, SYS_ICC_SRE_EL2 // Read SRE back,
tbz x0, #0, 1f // and check that it sticks
msr_s SYS_ICH_HCR_EL2, xzr // Reset ICC_HCR_EL2 to defaults
-1:
+.Lskip_gicv3_\@:
.endm

.macro __init_el2_hstr
@@ -128,14 +128,14 @@
.macro __init_el2_nvhe_sve
mrs x1, id_aa64pfr0_el1
ubfx x1, x1, #ID_AA64PFR0_SVE_SHIFT, #4
- cbz x1, 1f
+ cbz x1, .Lskip_sve_\@

bic x0, x0, #CPTR_EL2_TZ // Also disable SVE traps
msr cptr_el2, x0 // Disable copro. traps to EL2
isb
mov x1, #ZCR_ELx_LEN_MASK // SVE: Enable full vector
msr_s SYS_ZCR_EL2, x1 // length for EL1.
-1:
+.Lskip_sve_\@:
.endm

.macro __init_el2_nvhe_prepare_eret
--
2.29.2


2021-01-19 03:56:44

by David Brazdil

[permalink] [raw]
Subject: Re: [PATCH v4 01/21] arm64: Fix labels in el2_setup macros

On Mon, Jan 18, 2021 at 09:45:13AM +0000, Marc Zyngier wrote:
> If someone happens to write the following code:
>
> b 1f
> init_el2_state vhe
> 1:
> [...]
>
> they will be in for a long debugging session, as the label "1f"
> will be resolved *inside* the init_el2_state macro instead of
> after it. Not really what one expects.
>
> Instead, rewite the EL2 setup macros to use unambiguous labels,
> thanks to the usual macro counter trick.
>
> Acked-by: Catalin Marinas <[email protected]>
> Signed-off-by: Marc Zyngier <[email protected]>
> ---
> arch/arm64/include/asm/el2_setup.h | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)

Acked-by: David Brazdil <[email protected]>