Commit eb85a355 authored by Tony Lindgren's avatar Tony Lindgren
Browse files

ARM: OMAP: Fix SRAM W+X mapping 



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 728bbe75 ("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: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent ba688783

arch/arm/plat-omap/include/plat/sram.h

+1 −10
Original line number Diff line number Diff line
@@ -5,13 +5,4 @@ void omap_map_sram(unsigned long start, unsigned long size, 
			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);

arch/arm/plat-omap/sram.c

+35 −1
Original line number Diff line number Diff line
@@ -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 long size) 
	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 start, unsigned long size, 
	 */

	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);

}

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