[GIT PULL] arch_timer updates for v4.15

[GIT PULL] arch_timer updates for v4.15

[Mark Rutland]

Hi Daniel,

Please could you pull these arch timer updates for v4.15?

The first patch is a fix from Ard that fixes probling the MMIO timers on some
platforms. The other patch is a minor cleanup that prevents a warning when
building tags.

Thanks,
Mark.

The following changes since commit 9e66317d3c92ddaab330c125dfe9d06eee268aff:

  Linux 4.14-rc3 (2017-10-01 14:54:54 -0700)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git tags/arch-timer-4.15

for you to fetch changes up to cb3a23a029f6af0c73498b6a9773d6ec19541bf1:

  clocksource: arm_arch_timer: fix DEFINE_PER_CPU expansion (2017-10-16 15:37:16 +0100)

----------------------------------------------------------------
arch_timer updates for v4.15

- enable the MMIO CNTFRQ before reading it
- avoid a warning when building tags

----------------------------------------------------------------
Ard Biesheuvel (1):
      clocksource: arm_arch_timer: validate CNTFRQ after enabling frame

Mark Rutland (1):
      clocksource: arm_arch_timer: fix DEFINE_PER_CPU expansion

 drivers/clocksource/arm_arch_timer.c | 41 +++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 19 deletions(-)

[PATCH 1/2] clocksource: arm_arch_timer: validate CNTFRQ after enabling frame

[Mark Rutland]

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>

The ACPI GTDT code validates the CNTFRQ field of each MMIO timer
frame against the CNTFRQ system register of the current CPU, to
ensure that they are equal, which is mandated by the architecture.

However, reading the CNTFRQ field of a frame is not possible until
the RFRQ bit in the frame's CNTACRn register is set, and doing so
before that willl produce the following error:

  arch_timer: [Firmware Bug]: CNTFRQ mismatch: frame @ 0x00000000e0be0000: (0x00000000), CPU: (0x0ee6b280)
  arch_timer: Disabling MMIO timers due to CNTFRQ mismatch
  arch_timer: Failed to initialize memory-mapped timer.

The reason is that the CNTFRQ field is RES0 if access is not enabled.

So move the validation of CNTFRQ into the loop that iterates over the
timers to find the best frame, but defer it until after we have selected
the best frame, which should also have enabled the RFRQ bit.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
---
 drivers/clocksource/arm_arch_timer.c | 38 ++++++++++++++++++++----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index fd4b7f684bd0..14e2419063e9 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -1268,10 +1268,6 @@ arch_timer_mem_find_best_frame(struct arch_timer_mem *timer_mem)
 
 	iounmap(cntctlbase);
 
-	if (!best_frame)
-		pr_err("Unable to find a suitable frame in timer @ %pa\n",
-			&timer_mem->cntctlbase);
-
 	return best_frame;
 }
 
@@ -1372,6 +1368,8 @@ static int __init arch_timer_mem_of_init(struct device_node *np)
 
 	frame = arch_timer_mem_find_best_frame(timer_mem);
 	if (!frame) {
+		pr_err("Unable to find a suitable frame in timer @ %pa\n",
+			&timer_mem->cntctlbase);
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1420,7 +1418,7 @@ arch_timer_mem_verify_cntfrq(struct arch_timer_mem *timer_mem)
 static int __init arch_timer_mem_acpi_init(int platform_timer_count)
 {
 	struct arch_timer_mem *timers, *timer;
-	struct arch_timer_mem_frame *frame;
+	struct arch_timer_mem_frame *frame, *best_frame = NULL;
 	int timer_count, i, ret = 0;
 
 	timers = kcalloc(platform_timer_count, sizeof(*timers),
@@ -1432,14 +1430,6 @@ static int __init arch_timer_mem_acpi_init(int platform_timer_count)
 	if (ret || !timer_count)
 		goto out;
 
-	for (i = 0; i < timer_count; i++) {
-		ret = arch_timer_mem_verify_cntfrq(&timers[i]);
-		if (ret) {
-			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
-			goto out;
-		}
-	}
-
 	/*
 	 * While unlikely, it's theoretically possible that none of the frames
 	 * in a timer expose the combination of feature we want.
@@ -1448,12 +1438,26 @@ static int __init arch_timer_mem_acpi_init(int platform_timer_count)
 		timer = &timers[i];
 
 		frame = arch_timer_mem_find_best_frame(timer);
-		if (frame)
-			break;
+		if (!best_frame)
+			best_frame = frame;
+
+		ret = arch_timer_mem_verify_cntfrq(timer);
+		if (ret) {
+			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
+			goto out;
+		}
+
+		if (!best_frame) /* implies !frame */
+			/*
+			 * Only complain about missing suitable frames if we
+			 * haven't already found one in a previous iteration.
+			 */
+			pr_err("Unable to find a suitable frame in timer @ %pa\n",
+				&timer->cntctlbase);
 	}
 
-	if (frame)
-		ret = arch_timer_mem_frame_register(frame);
+	if (best_frame)
+		ret = arch_timer_mem_frame_register(best_frame);
 out:
 	kfree(timers);
 	return ret;
-- 
2.11.0

[PATCH 2/2] clocksource: arm_arch_timer: fix DEFINE_PER_CPU expansion

[Mark Rutland]

Our ctags mangling script can't handle newlines inside of a
DEFINE_PER_CPU(), leading to an annoying message whenever tags are
built:

  ctags: Warning: drivers/clocksource/arm_arch_timer.c:302: null expansion of name pattern "\1"

This was dealt with elsewhere in commit:

  25528213fe9f75f4 ("tags: Fix DEFINE_PER_CPU expansions")

... by ensuring each DEFINE_PER_CPU() was contained on a single line,
even where this would violate the usual code style (checkpatch warnings
and all).

Let's do the same for the arch timer driver, and get rid of the
distraction.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 drivers/clocksource/arm_arch_timer.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 14e2419063e9..0ecf5beb56ec 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -299,8 +299,7 @@ static u64 notrace arm64_858921_read_cntvct_el0(void)
 #endif
 
 #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
-DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *,
-	       timer_unstable_counter_workaround);
+DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround);
 EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
 
 DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
-- 
2.11.0

[PATCH] checkpatch: Allow DEFINE_PER_CPU definitions to exceed line length

[Joe Perches]

Some of the definitions are very long and can't be split
into multiple lines because ctags is limited.

Exempt these lines from the line length checks.

Signed-off-by: Joe Perches <joe@perches.com>
---
 scripts/checkpatch.pl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2a8c6c3c1bdb..5fa0f5467d99 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2900,8 +2900,9 @@ sub process {
 				 $line =~ /^\+\s*#\s*define\s+\w+\s+$String$/) {
 				$msg_type = "";
 
-			# EFI_GUID is another special case
-			} elsif ($line =~ /^\+.*\bEFI_GUID\s*\(/) {
+			# More special cases
+			} elsif ($line =~ /^\+.*\bEFI_GUID\s*\(/ ||
+				 $line =~ /^\+\s*(?:\w+)?\s*DEFINE_PER_CPU/) {
 				$msg_type = "";
 
 			# Otherwise set the alternate message types

[PATCH] checkpatch: Allow DEFINE_PER_CPU definitions to exceed line length

[Mark Rutland]

On Mon, Oct 16, 2017 at 09:12:00AM -0700, Joe Perches wrote:
> Some of the definitions are very long and can't be split
> into multiple lines because ctags is limited.
> 
> Exempt these lines from the line length checks.
> 
> Signed-off-by: Joe Perches <joe@perches.com>

It might make sense to point at commit:

  25528213fe9f75f4 ("tags: Fix DEFINE_PER_CPU expansions")

... for the gory details, but either way:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks,
Mark.

> ---
>  scripts/checkpatch.pl | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 2a8c6c3c1bdb..5fa0f5467d99 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2900,8 +2900,9 @@ sub process {
>  				 $line =~ /^\+\s*#\s*define\s+\w+\s+$String$/) {
>  				$msg_type = "";
>  
> -			# EFI_GUID is another special case
> -			} elsif ($line =~ /^\+.*\bEFI_GUID\s*\(/) {
> +			# More special cases
> +			} elsif ($line =~ /^\+.*\bEFI_GUID\s*\(/ ||
> +				 $line =~ /^\+\s*(?:\w+)?\s*DEFINE_PER_CPU/) {
>  				$msg_type = "";
>  
>  			# Otherwise set the alternate message types

[GIT PULL] arch_timer updates for v4.15

[Daniel Lezcano]

On 16/10/2017 17:28, Mark Rutland wrote:
> Hi Daniel,
> 
> Please could you pull these arch timer updates for v4.15?
> 
> The first patch is a fix from Ard that fixes probling the MMIO timers on some
> platforms. The other patch is a minor cleanup that prevents a warning when
> building tags.

Hi Mark,

I applied the patches for 4.15.

Thanks!

  -- Daniel

-- 
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