@@ -181,8 +181,19 @@ do { \
#endif
#ifdef __powerpc64__
+#ifdef CONFIG_PPC_KERNEL_PREFIXED
#define __get_user_asm2_goto(x, addr, label) \
__get_user_asm_goto(x, addr, label, "ld")
+#else
+#define __get_user_asm2_goto(x, addr, label) \
+ asm_goto_output( \
+ "1: ld%U1%X1 %0, %1 # get_user\n" \
+ EX_TABLE(1b, %l2) \
+ : "=r" (x) \
+ : DS_FORM_CONSTRAINT (*addr) \
+ : \
+ : label)
+#endif // CONFIG_PPC_KERNEL_PREFIXED
#else /* __powerpc64__ */
#define __get_user_asm2_goto(x, addr, label) \
asm_goto_output( \
The 'ld' instruction requires a 4-byte aligned displacement because it is a DS-form instruction. But the "m" asm constraint doesn't enforce that. Add a special case of __get_user_asm2_goto() so that the "YZ" constraint can be used for "ld". The "Z" constraint is documented in the GCC manual PowerPC machine constraints, and specifies a "memory operand accessed with indexed or indirect addressing". "Y" is not documented in the manual but specifies a "memory operand for a DS-form instruction". Using both allows the compiler to generate a DS-form "ld" or X-form "ldx" as appropriate. The change has to be conditional on CONFIG_PPC_KERNEL_PREFIXED because the "Y" constraint does not guarantee 4-byte alignment when prefixed instructions are enabled. No build errors have been reported due to this, but the possibility is there depending on compiler code generation decisions. Fixes: c20beffeec3c ("powerpc/uaccess: Use flexible addressing with __put_user()/__get_user()") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/include/asm/uaccess.h | 11 +++++++++++ 1 file changed, 11 insertions(+)