[PATCH AUTOSEL 4.14 01/12] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6

[PATCH AUTOSEL 4.14 01/12] ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6

[Sasha Levin]

From: Ard Biesheuvel <ardb@kernel.org>

[ Upstream commit f9e7a99fb6b86aa6a00e53b34ee6973840e005aa ]

The cache invalidation code in v7_invalidate_l1 can be tweaked to
re-read the associativity from CCSIDR, and keep the way identifier
component in a single register that is assigned in the outer loop. This
way, we need 2 registers less.

Given that the number of sets is typically much larger than the
associativity, rearrange the code so that the outer loop has the fewer
number of iterations, ensuring that the re-read of CCSIDR only occurs a
handful of times in practice.

Fix the whitespace while at it, and update the comment to indicate that
this code is no longer a clone of anything else.

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/mm/cache-v7.S | 51 +++++++++++++++++++++---------------------
 1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index 50a70edbc863..08986397e5c7 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -27,41 +27,40 @@
  * processor.  We fix this by performing an invalidate, rather than a
  * clean + invalidate, before jumping into the kernel.
  *
- * This function is cloned from arch/arm/mach-tegra/headsmp.S, and needs
- * to be called for both secondary cores startup and primary core resume
- * procedures.
+ * This function needs to be called for both secondary cores startup and
+ * primary core resume procedures.
  */
 ENTRY(v7_invalidate_l1)
        mov     r0, #0
        mcr     p15, 2, r0, c0, c0, 0
        mrc     p15, 1, r0, c0, c0, 0
 
-       movw    r1, #0x7fff
-       and     r2, r1, r0, lsr #13
+	movw	r3, #0x3ff
+	and	r3, r3, r0, lsr #3	@ 'Associativity' in CCSIDR[12:3]
+	clz	r1, r3			@ WayShift
+	mov	r2, #1
+	mov	r3, r3, lsl r1		@ NumWays-1 shifted into bits [31:...]
+	movs	r1, r2, lsl r1		@ #1 shifted left by same amount
+	moveq	r1, #1			@ r1 needs value > 0 even if only 1 way
 
-       movw    r1, #0x3ff
+	and	r2, r0, #0x7
+	add	r2, r2, #4		@ SetShift
 
-       and     r3, r1, r0, lsr #3      @ NumWays - 1
-       add     r2, r2, #1              @ NumSets
+1:	movw	r4, #0x7fff
+	and	r0, r4, r0, lsr #13	@ 'NumSets' in CCSIDR[27:13]
 
-       and     r0, r0, #0x7
-       add     r0, r0, #4      @ SetShift
-
-       clz     r1, r3          @ WayShift
-       add     r4, r3, #1      @ NumWays
-1:     sub     r2, r2, #1      @ NumSets--
-       mov     r3, r4          @ Temp = NumWays
-2:     subs    r3, r3, #1      @ Temp--
-       mov     r5, r3, lsl r1
-       mov     r6, r2, lsl r0
-       orr     r5, r5, r6      @ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
-       mcr     p15, 0, r5, c7, c6, 2
-       bgt     2b
-       cmp     r2, #0
-       bgt     1b
-       dsb     st
-       isb
-       ret     lr
+2:	mov	r4, r0, lsl r2		@ NumSet << SetShift
+	orr	r4, r4, r3		@ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
+	mcr	p15, 0, r4, c7, c6, 2
+	subs	r0, r0, #1		@ Set--
+	bpl	2b
+	subs	r3, r3, r1		@ Way--
+	bcc	3f
+	mrc	p15, 1, r0, c0, c0, 0	@ re-read cache geometry from CCSIDR
+	b	1b
+3:	dsb	st
+	isb
+	ret	lr
 ENDPROC(v7_invalidate_l1)
 
 /*
-- 
2.30.2


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[PATCH AUTOSEL 4.14 03/12] ARM: 9066/1: ftrace: pause/unpause function graph tracer in cpu_suspend()

[Sasha Levin]

From: "louis.wang" <liang26812@gmail.com>

[ Upstream commit 8252ca87c7a2111502ee13994956f8c309faad7f ]

Enabling function_graph tracer on ARM causes kernel panic, because the
function graph tracer updates the "return address" of a function in order
to insert a trace callback on function exit, it saves the function's
original return address in a return trace stack, but cpu_suspend() may not
return through the normal return path.

cpu_suspend() will resume directly via the cpu_resume path, but the return
trace stack has been set-up by the subfunctions of cpu_suspend(), which
makes the "return address" inconsistent with cpu_suspend().

This patch refers to Commit de818bd4522c40ea02a81b387d2fa86f989c9623
("arm64: kernel: pause/unpause function graph tracer in cpu_suspend()"),

fixes the issue by pausing/resuming the function graph tracer on the thread
executing cpu_suspend(), so that the function graph tracer state is kept
consistent across functions that enter power down states and never return
by effectively disabling graph tracer while they are executing.

Signed-off-by: louis.wang <liang26812@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/kernel/suspend.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index d08099269e35..e126386fb78a 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/mm_types.h>
@@ -26,6 +27,13 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	if (!idmap_pgd)
 		return -EINVAL;
 
+	/*
+	 * Function graph tracer state gets incosistent when the kernel
+	 * calls functions that never return (aka suspend finishers) hence
+	 * disable graph tracing during their execution.
+	 */
+	pause_graph_tracing();
+
 	/*
 	 * Provide a temporary page table with an identity mapping for
 	 * the MMU-enable code, required for resuming.  On successful
@@ -33,6 +41,9 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	 * back to the correct page tables.
 	 */
 	ret = __cpu_suspend(arg, fn, __mpidr);
+
+	unpause_graph_tracing();
+
 	if (ret == 0) {
 		cpu_switch_mm(mm->pgd, mm);
 		local_flush_bp_all();
@@ -46,7 +57,13 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 {
 	u32 __mpidr = cpu_logical_map(smp_processor_id());
-	return __cpu_suspend(arg, fn, __mpidr);
+	int ret;
+
+	pause_graph_tracing();
+	ret = __cpu_suspend(arg, fn, __mpidr);
+	unpause_graph_tracing();
+
+	return ret;
 }
 #define	idmap_pgd	NULL
 #endif
-- 
2.30.2


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