| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <aad81758-89fa-4aa8-8b64-d75003ce4e3b@linux.intel.com>
Date: Tue, 17 Jun 2025 16:00:21 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: kan.liang@...ux.intel.com, peterz@...radead.org, mingo@...hat.com,
acme@...nel.org, namhyung@...nel.org, tglx@...utronix.de,
dave.hansen@...ux.intel.com, irogers@...gle.com, adrian.hunter@...el.com,
jolsa@...nel.org, alexander.shishkin@...ux.intel.com,
linux-kernel@...r.kernel.org
Cc: ak@...ux.intel.com, zide.chen@...el.com
Subject: Re: [RFC PATCH 06/12] perf: Support extension of sample_regs
On 6/13/2025 9:49 PM, kan.liang@...ux.intel.com wrote:
> From: Kan Liang <kan.liang@...ux.intel.com>
>
> More regs may be required in a sample, e.g., the vector registers. The
> current sample_regs_XXX has run out of space.
>
> Add sample_ext_regs_intr/user[2] in the struct perf_event_attr. It's used
> as a bitmap for the extension regs. There will be more than 64 registers
> added.
> Add a new flag PERF_PMU_CAP_EXTENDED_REGS2 to indicate the PMU which
> supports sample_ext_regs_intr/user.
>
> Extend the perf_reg_validate() to support the validation of the
> extension regs.
>
> Extend the perf_reg_value() to retrieve the extension regs. The regs may
> be larger than u64. Add two parameters to store the pointer and size.
> Add a dedicated perf_output_sample_ext_regs() to dump the extension
> regs.
>
> This is just a generic support for the extension regs. Any attempts to
> manipulate the extension regs will error out, until the driver-specific
> supports are implemented, which will be done in the following patch.
>
> Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
> ---
> arch/arm/kernel/perf_regs.c | 9 +++--
> arch/arm64/kernel/perf_regs.c | 9 +++--
> arch/csky/kernel/perf_regs.c | 9 +++--
> arch/loongarch/kernel/perf_regs.c | 8 +++--
> arch/mips/kernel/perf_regs.c | 9 +++--
> arch/powerpc/perf/perf_regs.c | 9 +++--
> arch/riscv/kernel/perf_regs.c | 8 +++--
> arch/s390/kernel/perf_regs.c | 9 +++--
> arch/x86/kernel/perf_regs.c | 13 ++++++--
> include/linux/perf_event.h | 15 +++++++++
> include/linux/perf_regs.h | 29 +++++++++++++---
> include/uapi/linux/perf_event.h | 8 +++++
> kernel/events/core.c | 55 ++++++++++++++++++++++++++++---
> 13 files changed, 162 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm/kernel/perf_regs.c b/arch/arm/kernel/perf_regs.c
> index 0529f90395c9..b6161c30bd40 100644
> --- a/arch/arm/kernel/perf_regs.c
> +++ b/arch/arm/kernel/perf_regs.c
> @@ -8,8 +8,10 @@
> #include <asm/perf_regs.h>
> #include <asm/ptrace.h>
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM_MAX))
> return 0;
>
> @@ -18,8 +20,11 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>
> #define REG_RESERVED (~((1ULL << PERF_REG_ARM_MAX) - 1))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> +
> if (!mask || mask & REG_RESERVED)
> return -EINVAL;
>
> diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c
> index b4eece3eb17d..668b54a7faf9 100644
> --- a/arch/arm64/kernel/perf_regs.c
> +++ b/arch/arm64/kernel/perf_regs.c
> @@ -27,8 +27,10 @@ static u64 perf_ext_regs_value(int idx)
> }
> }
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_EXTENDED_MAX))
> return 0;
>
> @@ -77,10 +79,13 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>
> #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> u64 reserved_mask = REG_RESERVED;
>
> + if (mask_ext)
> + return -EINVAL;
> +
> if (system_supports_sve())
> reserved_mask &= ~(1ULL << PERF_REG_ARM64_VG);
>
> diff --git a/arch/csky/kernel/perf_regs.c b/arch/csky/kernel/perf_regs.c
> index 09b7f88a2d6a..5988ef55bf0a 100644
> --- a/arch/csky/kernel/perf_regs.c
> +++ b/arch/csky/kernel/perf_regs.c
> @@ -8,8 +8,10 @@
> #include <asm/perf_regs.h>
> #include <asm/ptrace.h>
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> if (WARN_ON_ONCE((u32)idx >= PERF_REG_CSKY_MAX))
> return 0;
>
> @@ -18,8 +20,11 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>
> #define REG_RESERVED (~((1ULL << PERF_REG_CSKY_MAX) - 1))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> +
> if (!mask || mask & REG_RESERVED)
> return -EINVAL;
>
> diff --git a/arch/loongarch/kernel/perf_regs.c b/arch/loongarch/kernel/perf_regs.c
> index 263ac4ab5af6..798dadee75ff 100644
> --- a/arch/loongarch/kernel/perf_regs.c
> +++ b/arch/loongarch/kernel/perf_regs.c
> @@ -25,8 +25,10 @@ u64 perf_reg_abi(struct task_struct *tsk)
> }
> #endif /* CONFIG_32BIT */
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask)
> return -EINVAL;
> if (mask & ~((1ull << PERF_REG_LOONGARCH_MAX) - 1))
> @@ -34,8 +36,10 @@ int perf_reg_validate(u64 mask)
> return 0;
> }
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> if (WARN_ON_ONCE((u32)idx >= PERF_REG_LOONGARCH_MAX))
> return 0;
>
> diff --git a/arch/mips/kernel/perf_regs.c b/arch/mips/kernel/perf_regs.c
> index e686780d1647..f3fcbf7e5aa6 100644
> --- a/arch/mips/kernel/perf_regs.c
> +++ b/arch/mips/kernel/perf_regs.c
> @@ -28,8 +28,10 @@ u64 perf_reg_abi(struct task_struct *tsk)
> }
> #endif /* CONFIG_32BIT */
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask)
> return -EINVAL;
> if (mask & ~((1ull << PERF_REG_MIPS_MAX) - 1))
> @@ -37,10 +39,13 @@ int perf_reg_validate(u64 mask)
> return 0;
> }
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> long v;
>
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> +
> switch (idx) {
> case PERF_REG_MIPS_PC:
> v = regs->cp0_epc;
> diff --git a/arch/powerpc/perf/perf_regs.c b/arch/powerpc/perf/perf_regs.c
> index 350dccb0143c..556466409c76 100644
> --- a/arch/powerpc/perf/perf_regs.c
> +++ b/arch/powerpc/perf/perf_regs.c
> @@ -99,8 +99,11 @@ static u64 get_ext_regs_value(int idx)
> }
> }
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> +
> if (idx == PERF_REG_POWERPC_SIER &&
> (IS_ENABLED(CONFIG_FSL_EMB_PERF_EVENT) ||
> IS_ENABLED(CONFIG_PPC32) ||
> @@ -125,8 +128,10 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
> return regs_get_register(regs, pt_regs_offset[idx]);
> }
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask || mask & REG_RESERVED)
> return -EINVAL;
> return 0;
> diff --git a/arch/riscv/kernel/perf_regs.c b/arch/riscv/kernel/perf_regs.c
> index fd304a248de6..05a4f1e7b243 100644
> --- a/arch/riscv/kernel/perf_regs.c
> +++ b/arch/riscv/kernel/perf_regs.c
> @@ -8,8 +8,10 @@
> #include <asm/perf_regs.h>
> #include <asm/ptrace.h>
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> if (WARN_ON_ONCE((u32)idx >= PERF_REG_RISCV_MAX))
> return 0;
>
> @@ -18,8 +20,10 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>
> #define REG_RESERVED (~((1ULL << PERF_REG_RISCV_MAX) - 1))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask || mask & REG_RESERVED)
> return -EINVAL;
>
> diff --git a/arch/s390/kernel/perf_regs.c b/arch/s390/kernel/perf_regs.c
> index a6b058ee4a36..2e17ae51279e 100644
> --- a/arch/s390/kernel/perf_regs.c
> +++ b/arch/s390/kernel/perf_regs.c
> @@ -7,10 +7,13 @@
> #include <asm/ptrace.h>
> #include <asm/fpu.h>
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> freg_t fp;
>
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> +
> if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
> return regs->gprs[idx];
>
> @@ -34,8 +37,10 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
>
> #define REG_RESERVED (~((1UL << PERF_REG_S390_MAX) - 1))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask || mask & REG_RESERVED)
> return -EINVAL;
>
> diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
> index 624703af80a1..b9d5106afc26 100644
> --- a/arch/x86/kernel/perf_regs.c
> +++ b/arch/x86/kernel/perf_regs.c
> @@ -57,10 +57,13 @@ static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
> #endif
> };
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx)
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> struct x86_perf_regs *perf_regs;
>
> + if (WARN_ON_ONCE(ext || ext_size))
> + return 0;
> +
> if (idx >= PERF_REG_X86_XMM0 && idx < PERF_REG_X86_XMM_MAX) {
> perf_regs = container_of(regs, struct x86_perf_regs, regs);
> if (!perf_regs->xmm_regs)
> @@ -87,8 +90,10 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
> (1ULL << PERF_REG_X86_R14) | \
> (1ULL << PERF_REG_X86_R15))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
> return -EINVAL;
>
> @@ -112,8 +117,10 @@ void perf_get_regs_user(struct perf_regs *regs_user,
> (1ULL << PERF_REG_X86_FS) | \
> (1ULL << PERF_REG_X86_GS))
>
> -int perf_reg_validate(u64 mask)
> +int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> + if (mask_ext)
> + return -EINVAL;
> if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
> return -EINVAL;
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 74c188a699e4..42b288ab4d2c 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -305,6 +305,7 @@ struct perf_event_pmu_context;
> #define PERF_PMU_CAP_EXTENDED_HW_TYPE 0x0100
> #define PERF_PMU_CAP_AUX_PAUSE 0x0200
> #define PERF_PMU_CAP_AUX_PREFER_LARGE 0x0400
> +#define PERF_PMU_CAP_EXTENDED_REGS2 0x0800 /* sample_ext_regs_intr/user */
>
> /**
> * pmu::scope
> @@ -1496,6 +1497,20 @@ static inline bool event_has_extended_regs(struct perf_event *event)
> (attr->sample_regs_intr & PERF_REG_EXTENDED_MASK);
> }
>
> +static inline bool event_has_extended_regs2(struct perf_event *event)
> +{
> + struct perf_event_attr *attr = &event->attr;
> + int i;
> +
> + for (i = 0; i < PERF_ATTR_EXT_REGS_SIZE; i++) {
> + if (attr->sample_ext_regs_intr[i] ||
> + attr->sample_ext_regs_user[i])
> + return true;
> + }
> +
> + return false;
> +}
> +
> static inline bool event_has_any_exclude_flag(struct perf_event *event)
> {
> struct perf_event_attr *attr = &event->attr;
> diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
> index f632c5725f16..6119bcb010fb 100644
> --- a/include/linux/perf_regs.h
> +++ b/include/linux/perf_regs.h
> @@ -16,23 +16,42 @@ struct perf_regs {
> #define PERF_REG_EXTENDED_MASK 0
> #endif
>
> -u64 perf_reg_value(struct pt_regs *regs, int idx);
> -int perf_reg_validate(u64 mask);
> +#define PERF_EXT_REGS_SIZE_MAX 8
> +
> +/**
> + * perf_reg_value - Get a reg value
> + * @regs: The area where stores all registers
> + * @idx: The index of the request register.
> + * The below @ext indicates the index is for
> + * a regular register or an extension register.
> + * @ext: Pointer to the buffer which stores the
> + * value of the request extension register.
> + * NULL means request for a regular register.
> + * @ext_size: Size of the extension register.
> + *
> + * If it fails, 0 returns.
> + * If it succeeds, for a regular register (!ext),
> + * the value of the register returns.
> + * For an extension register (ext), ext[0] returns.
> + */
> +u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size);
Better to add an separate perf_ext_reg_value() helper for extended
registers. Combining the extended regs into perf_reg_value() makes this
helper over-complicated and hard to understand.
> +int perf_reg_validate(u64 mask, u64 *mask_ext);
> u64 perf_reg_abi(struct task_struct *task);
> void perf_get_regs_user(struct perf_regs *regs_user,
> struct pt_regs *regs);
> #else
>
> #define PERF_REG_EXTENDED_MASK 0
> +#define PERF_EXT_REGS_SIZE_MAX 8
>
> -static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
> +static inline u64 perf_reg_value(struct pt_regs *regs, int idx, u64 *ext, int *ext_size)
> {
> return 0;
> }
>
> -static inline int perf_reg_validate(u64 mask)
> +static inline int perf_reg_validate(u64 mask, u64 *mask_ext)
> {
> - return mask ? -ENOSYS : 0;
> + return mask || mask_ext ? -ENOSYS : 0;
> }
>
> static inline u64 perf_reg_abi(struct task_struct *task)
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 78a362b80027..e22ba72efcdb 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -382,6 +382,10 @@ enum perf_event_read_format {
> #define PERF_ATTR_SIZE_VER6 120 /* Add: aux_sample_size */
> #define PERF_ATTR_SIZE_VER7 128 /* Add: sig_data */
> #define PERF_ATTR_SIZE_VER8 136 /* Add: config3 */
> +#define PERF_ATTR_SIZE_VER9 168 /* Add: sample_ext_regs_intr */
> + /* Add: sample_ext_regs_user */
> +
> +#define PERF_ATTR_EXT_REGS_SIZE 2
>
> /*
> * 'struct perf_event_attr' contains various attributes that define
> @@ -543,6 +547,10 @@ struct perf_event_attr {
> __u64 sig_data;
>
> __u64 config3; /* extension of config2 */
> +
> + /* extension of sample_regs_XXX */
> + __u64 sample_ext_regs_intr[PERF_ATTR_EXT_REGS_SIZE];
> + __u64 sample_ext_regs_user[PERF_ATTR_EXT_REGS_SIZE];
> };
>
> /*
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 7f0d98d73629..c4279e1bf91a 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7385,11 +7385,40 @@ perf_output_sample_regs(struct perf_output_handle *handle,
> for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
> u64 val;
>
> - val = perf_reg_value(regs, bit);
> + val = perf_reg_value(regs, bit, NULL, NULL);
> perf_output_put(handle, val);
> }
> }
>
> +static void
> +__perf_output_sample_ext_regs(struct perf_output_handle *handle,
> + struct pt_regs *regs, u64 mask, int base)
> +{
> + u64 val[PERF_EXT_REGS_SIZE_MAX];
> + int i, bit, size = 0;
> + DECLARE_BITMAP(_mask, 64);
> +
> + if (!mask)
> + return;
> + bitmap_from_u64(_mask, mask);
> + for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
> + perf_reg_value(regs, bit + base, val, &size);
> +
> + for (i = 0; i < size; i++)
> + perf_output_put(handle, val[i]);
> + }
> +}
> +
> +static void
> +perf_output_sample_ext_regs(struct perf_output_handle *handle,
> + struct pt_regs *regs, u64 *mask)
> +{
> + int i;
> +
> + for (i = 0; i < PERF_ATTR_EXT_REGS_SIZE; i++)
> + __perf_output_sample_ext_regs(handle, regs, mask[i], i * 64);
> +}
> +
> static void perf_sample_regs_user(struct perf_regs *regs_user,
> struct pt_regs *regs)
> {
> @@ -7940,9 +7969,14 @@ void perf_output_sample(struct perf_output_handle *handle,
>
> if (abi) {
> u64 mask = event->attr.sample_regs_user;
> + u64 *ext_mask = event->attr.sample_ext_regs_user;
> +
> perf_output_sample_regs(handle,
> data->regs_user.regs,
> mask);
> + perf_output_sample_ext_regs(handle,
> + data->regs_user.regs,
> + ext_mask);
> }
> }
>
> @@ -7971,10 +8005,14 @@ void perf_output_sample(struct perf_output_handle *handle,
>
> if (abi) {
> u64 mask = event->attr.sample_regs_intr;
> + u64 *ext_mask = event->attr.sample_ext_regs_intr;
>
> perf_output_sample_regs(handle,
> data->regs_intr.regs,
> mask);
> + perf_output_sample_ext_regs(handle,
> + data->regs_intr.regs,
> + ext_mask);
> }
> }
>
> @@ -12535,6 +12573,12 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
> if (ret)
> goto err_pmu;
>
> + if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS2) &&
> + event_has_extended_regs2(event)) {
> + ret = -EOPNOTSUPP;
> + goto err_destroy;
> + }
> +
> if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
> event_has_extended_regs(event)) {
> ret = -EOPNOTSUPP;
> @@ -13073,7 +13117,8 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
> }
>
> if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
> - ret = perf_reg_validate(attr->sample_regs_user);
> + ret = perf_reg_validate(attr->sample_regs_user,
> + attr->sample_ext_regs_user);
> if (ret)
> return ret;
> }
> @@ -13096,8 +13141,10 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
> if (!attr->sample_max_stack)
> attr->sample_max_stack = sysctl_perf_event_max_stack;
>
> - if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
> - ret = perf_reg_validate(attr->sample_regs_intr);
> + if (attr->sample_type & PERF_SAMPLE_REGS_INTR) {
> + ret = perf_reg_validate(attr->sample_regs_intr,
> + attr->sample_ext_regs_intr);
> + }
>
> #ifndef CONFIG_CGROUP_PERF
> if (attr->sample_type & PERF_SAMPLE_CGROUP)
Powered by blists - more mailing lists