Provide register zeroing macros, following the same convention as
existing register stack save/restore macros, to be used in later
change to concisely zero a sequence of consecutive gprs.
The resulting macros are called ZEROIZE_GPRS and ZEROIZE_NVGPRS, keeping
with the naming of the accompanying restore and save macros, and usage
of zeroize to describe this operation elsewhere in the kernel.
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npig...@gmail.com>
---
V2: Change 'ZERO' usage in naming to 'NULLIFY', a more obvious verb
V3: Change 'NULLIFY' usage in naming to 'ZEROIZE', which has
ent in kernel and explicitly specifies that we are zeroing.
V4: Update commit message to use zeroize.
V5: The reason for the patch is to add zeroize macros. Move that
to first paragraph in patch description.
---
arch/powerpc/include/asm/ppc_asm.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/arch/powerpc/include/asm/ppc_asm.h
b/arch/powerpc/include/asm/ppc_asm.h
index 83c02f5a7f2a..b95689ada59c 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -33,6 +33,20 @@
.endr
.endm
+/*
+ * This expands to a sequence of register clears for regs start to end
+ * inclusive, of the form:
+ *
+ * li rN, 0
+ */
+.macro ZEROIZE_REGS start, end
+ .Lreg=\start
+ .rept (\end - \start + 1)
+ li .Lreg, 0
+ .Lreg=.Lreg+1
+ .endr
+.endm
+
/*
* Macros for storing registers into and loading registers from
* exception frames.
@@ -49,6 +63,14 @@
#define REST_NVGPRS(base) REST_GPRS(13, 31, base)
#endif
+#define ZEROIZE_GPRS(start, end) ZEROIZE_REGS start, end
+#ifdef __powerpc64__
+#define ZEROIZE_NVGPRS() ZEROIZE_GPRS(14, 31)
+#else
+#define ZEROIZE_NVGPRS() ZEROIZE_GPRS(13, 31)
+#endif
+#define ZEROIZE_GPR(n) ZEROIZE_GPRS(n, n)
+
#define SAVE_GPR(n, base) SAVE_GPRS(n, n, base)
#define REST_GPR(n, base) REST_GPRS(n, n, base)
--
2.34.1
