[tip: timers/core] clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses

tip-bot2 for Marc Zyngier
2021-10-24T15:40:48Z

The following commit has been merged into the timers/core branch of tip:

Commit-ID: 4775bc63f880001ee4fbd6456b12ab04674149e3
Gitweb: https://git.kernel.org/tip/4775bc63f880001ee4fbd6456b12ab04674149e3
Author: Marc Zyngier <maz@kernel.org>
AuthorDate: Sun, 17 Oct 2021 13:42:09 +01:00
Committer: Daniel Lezcano <daniel.lezcano@linaro.org>
CommitterDate: Sun, 17 Oct 2021 21:45:48 +02:00

clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses

As we are about to change the registers that are used by the driver,
start by adding build-time checks to ensure that we always handle
all registers and access modes.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211017124225.3018098-2-maz@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
arch/arm/include/asm/arch_timer.h | 12 ++++++++++++
arch/arm64/include/asm/arch_timer.h | 13 ++++++++++++-
drivers/clocksource/arm_arch_timer.c | 8 ++++++++
3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
index 9917581..a5d27cf 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -34,6 +34,8 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
case ARCH_TIMER_REG_TVAL:
asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
break;
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_VIRT_ACCESS) {
switch (reg) {
@@ -43,7 +45,11 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
case ARCH_TIMER_REG_TVAL:
asm volatile("mcr p15, 0, %0, c14, c3, 0" : : "r" (val));
break;
+ default:
+ BUILD_BUG();
}
+ } else {
+ BUILD_BUG();
}

isb();
@@ -62,6 +68,8 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
case ARCH_TIMER_REG_TVAL:
asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
break;
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_VIRT_ACCESS) {
switch (reg) {
@@ -71,7 +79,11 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
case ARCH_TIMER_REG_TVAL:
asm volatile("mrc p15, 0, %0, c14, c3, 0" : "=r" (val));
break;
+ default:
+ BUILD_BUG();
}
+ } else {
+ BUILD_BUG();
}

return val;
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 88d20f0..fa12ea4 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -112,6 +112,8 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
case ARCH_TIMER_REG_TVAL:
write_sysreg(val, cntp_tval_el0);
break;
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_VIRT_ACCESS) {
switch (reg) {
@@ -121,7 +123,11 @@ void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
case ARCH_TIMER_REG_TVAL:
write_sysreg(val, cntv_tval_el0);
break;
+ default:
+ BUILD_BUG();
}
+ } else {
+ BUILD_BUG();
}

isb();
@@ -136,6 +142,8 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
return read_sysreg(cntp_ctl_el0);
case ARCH_TIMER_REG_TVAL:
return arch_timer_reg_read_stable(cntp_tval_el0);
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_VIRT_ACCESS) {
switch (reg) {
@@ -143,10 +151,13 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
return read_sysreg(cntv_ctl_el0);
case ARCH_TIMER_REG_TVAL:
return arch_timer_reg_read_stable(cntv_tval_el0);
+ default:
+ BUILD_BUG();
}
}

- BUG();
+ BUILD_BUG();
+ unreachable();
}

static inline u32 arch_timer_get_cntfrq(void)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index be6d741..3b7d46d 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -112,6 +112,8 @@ void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
case ARCH_TIMER_REG_TVAL:
writel_relaxed(val, timer->base + CNTP_TVAL);
break;
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
@@ -122,6 +124,8 @@ void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
case ARCH_TIMER_REG_TVAL:
writel_relaxed(val, timer->base + CNTV_TVAL);
break;
+ default:
+ BUILD_BUG();
}
} else {
arch_timer_reg_write_cp15(access, reg, val);
@@ -143,6 +147,8 @@ u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
case ARCH_TIMER_REG_TVAL:
val = readl_relaxed(timer->base + CNTP_TVAL);
break;
+ default:
+ BUILD_BUG();
}
} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
struct arch_timer *timer = to_arch_timer(clk);
@@ -153,6 +159,8 @@ u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
case ARCH_TIMER_REG_TVAL:
val = readl_relaxed(timer->base + CNTV_TVAL);
break;
+ default:
+ BUILD_BUG();
}
} else {
val = arch_timer_reg_read_cp15(access, reg);