ARM: proc-arm94*.S: fix setup function
Both ARM946 and ARM940 setup functions were corrupting r1 and r2,
which is not permissible - these are used to carry the machine ID
and boot data into the kernel, and must be preserved.
The code responsible for this was the same in both files: they were
using the registers to generate a protection region register value.
Fix this by turning this process into a macro, and using that macro
in both these files with an alternative register allocation. r0,
r3 and r7 can be used for temporary values here.
Reported-by: Alex Dumitrache <broscutamaker@gmail.com>
Tested-by: Georg Hofstetter <g3gg0.de@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index 082b9f2..d081c9d 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -331,3 +331,27 @@
.globl \x
.equ \x, \y
.endm
+
+ /*
+ * Macro to calculate the log2 size for the protection region
+ * registers. This calculates rd = log2(size) - 1. tmp must
+ * not be the same register as rd.
+ */
+.macro pr_sz, rd, size, tmp
+ mov \tmp, \size, lsr #12
+ mov \rd, #11
+1: movs \tmp, \tmp, lsr #1
+ addne \rd, \rd, #1
+ bne 1b
+.endm
+
+ /*
+ * Macro to generate a protection region register value
+ * given a pre-masked address, size, and enable bit.
+ * Corrupts size.
+ */
+.macro pr_val, dest, addr, size, enable
+ pr_sz \dest, \size, \size @ calculate log2(size) - 1
+ orr \dest, \addr, \dest, lsl #1 @ mask in the region size
+ orr \dest, \dest, \enable
+.endm