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Groups > linux.kernel > #1329226
| From | Catalin Marinas <catalin.marinas@arm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP |
| Date | 2016-02-08 17:00 +0100 |
| Message-ID | <qZWoi-7it-9@gated-at.bofh.it> (permalink) |
| References | <qYa2m-5r0-3@gated-at.bofh.it> <qYa2m-5r0-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Feb 03, 2016 at 06:00:14PM +0000, Marc Zyngier wrote:
> @@ -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));
I don't particularly like this part as it's not clear just by looking at
the code that it, in fact, generates AARCH64_BREAKPOINT_EL1. I would
make this clearer:
if (is_kernel_in_hyp_mode() && (reg & (DBG_HMC_HYP >> 1)))
ctrl->privilege = AARCH64_BREAKPOINT_EL1;
Alternatively, you could define the PMC field value as:
#define AARCH64_BREAKPOINT_EL2 0
and change the privilege to EL1 after masking, something like:
ctrl->privilege = reg & 0x3;
if (ctrl->privilege == AARCH64_BREAKPOINT_EL2)
ctrl->privilege = AARCH64_BREAKPOINT_EL1;
BTW, do we need to check is_kernel_in_hyp_mode() when decoding? Is there
anything else that could have set this SSC/HMC/PMC fields other than
encode_ctrl_reg()?
--
Catalin
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[PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP Marc Zyngier <marc.zyngier@arm.com> - 2016-02-03 19:10 +0100
Re: [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP Catalin Marinas <catalin.marinas@arm.com> - 2016-02-08 17:00 +0100
Re: [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP Marc Zyngier <marc.zyngier@arm.com> - 2016-02-08 17:50 +0100
Re: [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP Catalin Marinas <catalin.marinas@arm.com> - 2016-02-08 18:00 +0100
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