[PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP

Marc Zyngier
2016-02-03T18:01:44Z

With VHE, we place kernel {watch,break}-points at EL2 to get things
like kgdb and "perf -e mem:..." working.

This requires a bit of repainting in the low-level encore/decode,
but is otherwise pretty simple.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/hw_breakpoint.h | 49 +++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h
index 9732908..0da0272 100644
--- a/arch/arm64/include/asm/hw_breakpoint.h
+++ b/arch/arm64/include/asm/hw_breakpoint.h
@@ -18,6 +18,7 @@

#include <asm/cputype.h>
#include <asm/cpufeature.h>
+#include <asm/virt.h>

#ifdef __KERNEL__

@@ -35,24 +36,6 @@ struct arch_hw_breakpoint {
struct arch_hw_breakpoint_ctrl ctrl;
};

-static inline u32 encode_ctrl_reg(struct arch_hw_breakpoint_ctrl ctrl)
-{
- return (ctrl.len << 5) | (ctrl.type << 3) | (ctrl.privilege << 1) |
- ctrl.enabled;
-}
-
-static inline void decode_ctrl_reg(u32 reg,
- struct arch_hw_breakpoint_ctrl *ctrl)
-{
- ctrl->enabled = reg & 0x1;
- reg >>= 1;
- ctrl->privilege = reg & 0x3;
- reg >>= 2;
- ctrl->type = reg & 0x3;
- reg >>= 2;
- ctrl->len = reg & 0xff;
-}
-
/* Breakpoint */
#define ARM_BREAKPOINT_EXECUTE 0

@@ -76,6 +59,36 @@ static inline void decode_ctrl_reg(u32 reg,
#define ARM_KERNEL_STEP_ACTIVE 1
#define ARM_KERNEL_STEP_SUSPEND 2

+#define DBG_HMC_HYP (1 << 13)
+#define DBG_SSC_HYP (3 << 14)
+
+static inline u32 encode_ctrl_reg(struct arch_hw_breakpoint_ctrl ctrl)
+{
+ u32 val = (ctrl.len << 5) | (ctrl.type << 3) | ctrl.enabled;
+
+ if (is_kernel_in_hyp_mode() && ctrl.privilege == AARCH64_BREAKPOINT_EL1)
+ val |= DBG_HMC_HYP | DBG_SSC_HYP;
+ else
+ val |= ctrl.privilege << 1;
+
+ return val;
+}
+
+static inline void decode_ctrl_reg(u32 reg,
+ struct arch_hw_breakpoint_ctrl *ctrl)
+{
+ ctrl->enabled = reg & 0x1;
+ reg >>= 1;
+ if (is_kernel_in_hyp_mode())
+ ctrl->privilege = !!(reg & (DBG_HMC_HYP >> 1));
+ else
+ ctrl->privilege = reg & 0x3;
+ reg >>= 2;
+ ctrl->type = reg & 0x3;
+ reg >>= 2;
+ ctrl->len = reg & 0xff;
+}
+
/*
* Limits.
* Changing these will require modifications to the register accessors.
--
2.1.4