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authorThomas Bogendoerfer <tbogendoerfer@suse.de>2019-10-09 15:27:15 +0200
committerPaul Burton <paul.burton@mips.com>2019-10-09 14:55:53 -0700
commit351889d356290554bf5d20d684244813a654afbe (patch)
tree889b69d1c16509a8033b1a5b706363ed98e16073 /arch/mips/fw
parent39b2d7565a4736a30c6eeb550901433b44aebf57 (diff)
downloadlinux-351889d356290554bf5d20d684244813a654afbe.tar.bz2
MIPS: fw: arc: workaround 64bit kernel/32bit ARC problems
Pointer arguments for 32bit ARC PROMs must reside in CKSEG0/1. While the initial stack resides in CKSEG0 the first kernel thread stack is already placed at a XKPHYS address, which ARC32 can't handle. The workaround here is to use static variables, which are placed into BSS and linked to a CKSEG0 address. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'arch/mips/fw')
-rw-r--r--arch/mips/fw/arc/promlib.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/arch/mips/fw/arc/promlib.c b/arch/mips/fw/arc/promlib.c
index be381307fbb0..5e9e840a9314 100644
--- a/arch/mips/fw/arc/promlib.c
+++ b/arch/mips/fw/arc/promlib.c
@@ -11,6 +11,21 @@
#include <asm/bcache.h>
#include <asm/setup.h>
+#if defined(CONFIG_64BIT) && defined(CONFIG_FW_ARC32)
+/*
+ * For 64bit kernels working with a 32bit ARC PROM pointer arguments
+ * for ARC calls need to reside in CKEG0/1. But as soon as the kernel
+ * switches to it's first kernel thread stack is set to an address in
+ * XKPHYS, so anything on stack can't be used anymore. This is solved
+ * by using a * static declartion variables are put into BSS, which is
+ * linked to a CKSEG0 address. Since this is only used on UP platforms
+ * there is not spinlock needed
+ */
+#define O32_STATIC static
+#else
+#define O32_STATIC
+#endif
+
/*
* IP22 boardcache is not compatible with board caches. Thus we disable it
* during romvec action. Since r4xx0.c is always compiled and linked with your
@@ -23,8 +38,10 @@
void prom_putchar(char c)
{
- ULONG cnt;
- CHAR it = c;
+ O32_STATIC ULONG cnt;
+ O32_STATIC CHAR it;
+
+ it = c;
bc_disable();
ArcWrite(1, &it, 1, &cnt);
@@ -33,8 +50,8 @@ void prom_putchar(char c)
char prom_getchar(void)
{
- ULONG cnt;
- CHAR c;
+ O32_STATIC ULONG cnt;
+ O32_STATIC CHAR c;
bc_disable();
ArcRead(0, &c, 1, &cnt);