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Message-ID: <20240621073910.8465-3-yangtiezhu@loongson.cn>
Date: Fri, 21 Jun 2024 15:39:09 +0800
From: Tiezhu Yang <yangtiezhu@...ngson.cn>
To: Will Deacon <will@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Oleg Nesterov <oleg@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org,
linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] arm: hw_breakpoint: Save privilege of access control via ptrace
Currently, decode_ctrl_reg() saves the privilege of access control
which is not used anymore, arch_build_bp_info() checks whether bp
virtual address is in kernel space to construct hw->ctrl.privilege,
the process seems not reasonable.
The value of ctrl->privilege saved in decode_ctrl_reg() can be used
in arch_build_bp_info(), there is no need to check bp virtual address
to assign value for hw->ctrl.privilege, just make use of "bp_priv" in
the struct perf_event_attr to save the privilege of access control via
ptrace for hardware breakpoint.
Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
arch/arm/kernel/hw_breakpoint.c | 4 +---
arch/arm/kernel/ptrace.c | 2 ++
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
index a12efd0f43e8..7720d39473d9 100644
--- a/arch/arm/kernel/hw_breakpoint.c
+++ b/arch/arm/kernel/hw_breakpoint.c
@@ -568,9 +568,7 @@ static int arch_build_bp_info(struct perf_event *bp,
hw->address = attr->bp_addr;
/* Privilege */
- hw->ctrl.privilege = ARM_BREAKPOINT_USER;
- if (arch_check_bp_in_kernelspace(hw))
- hw->ctrl.privilege |= ARM_BREAKPOINT_PRIV;
+ hw->ctrl.privilege = attr->bp_priv;
/* Enabled? */
hw->ctrl.enabled = !attr->disabled;
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index c421a899fc84..0d6d6b2a57a0 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -422,6 +422,7 @@ static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
attr.bp_addr = 0;
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = type;
+ attr.bp_priv = ARM_BREAKPOINT_USER;
attr.disabled = 1;
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
@@ -530,6 +531,7 @@ static int ptrace_sethbpregs(struct task_struct *tsk, long num,
attr.bp_len = gen_len;
attr.bp_type = gen_type;
+ attr.bp_priv = ctrl.privilege;
attr.disabled = !ctrl.enabled;
}
--
2.42.0
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