This is a note to let you know that I've just added the patch titled

ARM: OMAP: Fix SRAM W+X mapping

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: arm-omap-fix-sram-w-x-mapping.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From eb85a355c3afd9379f5953cfe2df73632d14c884 Mon Sep 17 00:00:00 2001

From: Tony Lindgren tony@atomide.com Date: Wed, 21 Mar 2018 08:16:29 -0700 Subject: ARM: OMAP: Fix SRAM W+X mapping

From: Tony Lindgren tony@atomide.com

commit eb85a355c3afd9379f5953cfe2df73632d14c884 upstream.

We are still using custom SRAM code for some SoCs and are not marking the PM code mapped to SRAM as read-only and executable after we're done. With CONFIG_DEBUG_WX=y, we will get "Found insecure W+X mapping at address" warning.

Let's fix this issue the same way as commit 728bbe75c82f ("misc: sram: Introduce support code for protect-exec sram type") is doing for drivers/misc/sram-exec.c.

On omap3, we need to restore SRAM when returning from off mode after idle, so init time configuration is not enough.

And as we no longer have users for omap_sram_push_address() we can make it static while at it.

Note that eventually we should be using sram-exec.c for all SoCs.

Cc: stable@vger.kernel.org # v4.12+ Cc: Dave Gerlach d-gerlach@ti.com Reported-by: Pavel Machek pavel@ucw.cz Signed-off-by: Tony Lindgren tony@atomide.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/arm/plat-omap/include/plat/sram.h | 11 ---------- arch/arm/plat-omap/sram.c | 36 ++++++++++++++++++++++++++++++++- 2 files changed, 36 insertions(+), 11 deletions(-)

--- a/arch/arm/plat-omap/include/plat/sram.h +++ b/arch/arm/plat-omap/include/plat/sram.h @@ -5,13 +5,4 @@ void omap_map_sram(unsigned long start, unsigned long skip, int cached); void omap_sram_reset(void);

-extern void *omap_sram_push_address(unsigned long size); - -/* Macro to push a function to the internal SRAM, using the fncpy API */ -#define omap_sram_push(funcp, size) ({ \ - typeof(&(funcp)) _res = NULL; \ - void *_sram_address = omap_sram_push_address(size); \ - if (_sram_address) \ - _res = fncpy(_sram_address, &(funcp), size); \ - _res; \ -}) +extern void *omap_sram_push(void *funcp, unsigned long size); --- a/arch/arm/plat-omap/sram.c +++ b/arch/arm/plat-omap/sram.c @@ -23,6 +23,7 @@ #include <asm/fncpy.h> #include <asm/tlb.h> #include <asm/cacheflush.h> +#include <asm/set_memory.h>

#include <asm/mach/map.h>

@@ -42,7 +43,7 @@ static void __iomem *omap_sram_ceil; * Note that fncpy requires the returned address to be aligned * to an 8-byte boundary. */ -void *omap_sram_push_address(unsigned long size) +static void *omap_sram_push_address(unsigned long size) { unsigned long available, new_ceil = (unsigned long)omap_sram_ceil;

@@ -60,6 +61,30 @@ void *omap_sram_push_address(unsigned lo return (void *)omap_sram_ceil; }

+void *omap_sram_push(void *funcp, unsigned long size) +{ + void *sram; + unsigned long base; + int pages; + void *dst = NULL; + + sram = omap_sram_push_address(size); + if (!sram) + return NULL; + + base = (unsigned long)sram & PAGE_MASK; + pages = PAGE_ALIGN(size) / PAGE_SIZE; + + set_memory_rw(base, pages); + + dst = fncpy(sram, funcp, size); + + set_memory_ro(base, pages); + set_memory_x(base, pages); + + return dst; +} + /* * The SRAM context is lost during off-idle and stack * needs to be reset. @@ -75,6 +100,9 @@ void omap_sram_reset(void) void __init omap_map_sram(unsigned long start, unsigned long size, unsigned long skip, int cached) { + unsigned long base; + int pages; + if (size == 0) return;

@@ -95,4 +123,10 @@ void __init omap_map_sram(unsigned long */ memset_io(omap_sram_base + omap_sram_skip, 0, omap_sram_size - omap_sram_skip); + + base = (unsigned long)omap_sram_base; + pages = PAGE_ALIGN(omap_sram_size) / PAGE_SIZE; + + set_memory_ro(base, pages); + set_memory_x(base, pages); }

Patches currently in stable-queue which might be from tony@atomide.com are

queue-4.15/arm-omap-fix-sram-w-x-mapping.patch