Explicitly truncate the second operand of do_div() to 32 bits to guard
against bogus code calling it with a 64-bit divisor.
Based on commit ea077b1b96e073eac5c3c5590529e964767fc5f7 ("m68k: Truncate
base in do_div()")
While it doesn't really hurt on little-endian mn10300, unlike on m68k,
mn10300 was the only remaining architecture not doing this.
Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org>
---
Compile-tested only.
arch/mn10300/include/asm/div64.h | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/mn10300/include/asm/div64.h b/arch/mn10300/include/asm/div64.h
index 503efab..ff69f34 100644
--- a/arch/mn10300/include/asm/div64.h
+++ b/arch/mn10300/include/asm/div64.h
@@ -36,12 +36,13 @@ extern void ____unhandled_size_in_do_div___(void);
#define do_div(n, base)
\
({ \
unsigned __rem = 0; \
+ unsigned __base = (base); \
if (sizeof(n) <= 4) { \
asm("mov %1,mdr \n" \
"divu %2,%0 \n" \
"mov mdr,%1 \n" \
: "+r"(n), "=d"(__rem) \
- : "r"(base), "1"(__rem) \
+ : "r"(__base), "1"(__rem) \
: CLOBBER_MDR_CC \
); \
} else if (sizeof(n) <= 8) { \
@@ -52,14 +53,14 @@ extern void ____unhandled_size_in_do_div___(void);
__quot.l = n; \
asm("mov %0,mdr \n" /* MDR = 0 */ \
"divu %3,%1 \n" \
- /* __quot.MSL = __div.MSL / base, */ \
- /* MDR = MDR:__div.MSL % base */ \
+ /* __quot.MSL = __div.MSL / __base, */ \
+ /* MDR = MDR:__div.MSL % __base */ \
"divu %3,%2 \n" \
- /* __quot.LSL = MDR:__div.LSL / base, */ \
- /* MDR = MDR:__div.LSL % base */ \
+ /* __quot.LSL = MDR:__div.LSL / __base, */ \
+ /* MDR = MDR:__div.LSL % __base */ \
"mov mdr,%0 \n" \
: "=d"(__rem), "=r"(__quot.w[1]), "=r"(__quot.w[0]) \
- : "r"(base), "0"(__rem), "1"(__quot.w[1]), \
+ : "r"(__base), "0"(__rem), "1"(__quot.w[1]), \
"2"(__quot.w[0]) \
: CLOBBER_MDR_CC \
); \
--
1.7.9.5
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