Commit 2ba85e7a authored Aug 08, 2013 by Russell King

ARM: Fix FIQ code on VIVT CPUs



Aaro Koskinen reports the following oops:
Installing fiq handler from c001b110, length 0x164
Unable to handle kernel paging request at virtual address ffff1224
pgd = c0004000
[ffff1224] *pgd=00000000, *pte=11fff0cb, *ppte=11fff00a
...
[<c0013154>] (set_fiq_handler+0x0/0x6c) from [<c0365d38>] (ams_delta_init_fiq+0xa8/0x160)
 r6:00000164 r5:c001b110 r4:00000000 r3:fefecb4c
[<c0365c90>] (ams_delta_init_fiq+0x0/0x160) from [<c0365b14>] (ams_delta_init+0xd4/0x114)
 r6:00000000 r5:fffece10 r4:c037a9e0
[<c0365a40>] (ams_delta_init+0x0/0x114) from [<c03613b4>] (customize_machine+0x24/0x30)

This is because the vectors page is now write-protected, and to change
code in there we must write to its original alias.  Make that change,
and adjust the cache flushing such that the code will become visible
to the instruction stream on VIVT CPUs.

Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent 1b16c4bc

arch/arm/kernel/fiq.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -84,17 +84,13 @@ int show_fiq_list(struct seq_file *p, int prec)

		void set_fiq_handler(void *start, unsigned int length)
		{
		#if defined(CONFIG_CPU_USE_DOMAINS)
		void base = (void )0xffff0000;
		#else
		void *base = vectors_page;
		#endif
		unsigned offset = FIQ_OFFSET;

		memcpy(base + offset, start, length);
		if (!cache_is_vipt_nonaliasing())
		flush_icache_range(base + offset, offset + length);
		flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length);
		if (!vectors_high())
		flush_icache_range(offset, offset + length);
		}

		int claim_fiq(struct fiq_handler *f)

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