Commit e8184e10 authored Jul 26, 2013 by Geert Uytterhoeven

m68k/atari: ARAnyM - Fix NatFeat module support



As pointed out by Andreas Schwab, pointers passed to ARAnyM NatFeat calls
should be physical addresses, not virtual addresses.

Fortunately on Atari, physical and virtual kernel addresses are the same,
as long as normal kernel memory is concerned, so this usually worked fine
without conversion.

But for modules, pointers to literal strings are located in vmalloc()ed
memory. Depending on the version of ARAnyM, this causes the nf_get_id()
call to just fail, or worse, crash ARAnyM itself with e.g.

    Gotcha! Illegal memory access. Atari PC = $968c

This is a big issue for distro kernels, who want to have all drivers as
loadable modules in an initrd.

Add a wrapper for nf_get_id() that copies the literal to the stack to
work around this issue.

Reported-by: Thorsten Glaser <tg@debian.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org

parent d4e4ab86

arch/m68k/emu/natfeat.c

+19 −4

Original line number	Diff line number	Diff line
		@@ -18,9 +18,11 @@
		#include <asm/machdep.h>
		#include <asm/natfeat.h>

		extern long nf_get_id2(const char *feature_name);

		asm("\n"
		" .global nf_get_id,nf_call\n"
		"nf_get_id:\n"
		" .global nf_get_id2,nf_call\n"
		"nf_get_id2:\n"
		" .short 0x7300\n"
		" rts\n"
		"nf_call:\n"
		@@ -29,12 +31,25 @@ asm("\n"
		"1: moveq.l #0,%d0\n"
		" rts\n"
		" .section __ex_table,\"a\"\n"
		" .long nf_get_id,1b\n"
		" .long nf_get_id2,1b\n"
		" .long nf_call,1b\n"
		" .previous");
		EXPORT_SYMBOL_GPL(nf_get_id);
		EXPORT_SYMBOL_GPL(nf_call);

		long nf_get_id(const char *feature_name)
		{
		/* feature_name may be in vmalloc()ed memory, so make a copy */
		char name_copy[32];
		size_t n;

		n = strlcpy(name_copy, feature_name, sizeof(name_copy));
		if (n >= sizeof(name_copy))
		return 0;

		return nf_get_id2(name_copy);
		}
		EXPORT_SYMBOL_GPL(nf_get_id);

		void nfprint(const char *fmt, ...)
		{
		static char buf[256];

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