[PATCH v5 1/6] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

Prabhakar
2022-12-12T11:55:47Z

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Introduce ALTERNATIVE_3() macro.

A vendor wants to replace an old_content, but another vendor has used
ALTERNATIVE_2() to patch its customized content at the same location.
In this case, this vendor can use macro ALTERNATIVE_3() and then replace
ALTERNATIVE_2() with ALTERNATIVE_3() to append its customized content.

While at it update comment above ALTERNATIVE_2() macro and make it generic
so that the comment holds good for any new addition of ALTERNATIVE_X()
macros.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v4->v5
* Rebased the patch on top of Andrew's series (now in Palmers for next-branch)
* Updated comment for ALTERNATIVE_x() as suggested by Heiko

RFC v3 -> v4
* New patch
---
arch/riscv/include/asm/alternative-macros.h | 46 ++++++++++++++++++---
1 file changed, 41 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
index 7226e2462584..a5b4691520da 100644
--- a/arch/riscv/include/asm/alternative-macros.h
+++ b/arch/riscv/include/asm/alternative-macros.h
@@ -50,8 +50,17 @@
ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
.endm

+.macro ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
+ new_c_2, vendor_id_2, errata_id_2, enable_2, \
+ new_c_3, vendor_id_3, errata_id_3, enable_3
+ ALTERNATIVE_CFG_2 \old_c, \new_c_1, \vendor_id_1, \errata_id_1, \enable_1, \
+ \new_c_2, \vendor_id_2, \errata_id_2, \enable_2
+ ALT_NEW_CONTENT \vendor_id_3, \errata_id_3, \enable_3, \new_c_3
+.endm
+
#define __ALTERNATIVE_CFG(...) ALTERNATIVE_CFG __VA_ARGS__
#define __ALTERNATIVE_CFG_2(...) ALTERNATIVE_CFG_2 __VA_ARGS__
+#define __ALTERNATIVE_CFG_3(...) ALTERNATIVE_CFG_3 __VA_ARGS__

#else /* !__ASSEMBLY__ */

@@ -98,6 +107,13 @@
__ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1) \
ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_2)

+#define __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
+ new_c_2, vendor_id_2, errata_id_2, enable_2, \
+ new_c_3, vendor_id_3, errata_id_3, enable_3) \
+ __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
+ new_c_2, vendor_id_2, errata_id_2, enable_2) \
+ ALT_NEW_CONTENT(vendor_id_3, errata_id_3, enable_3, new_c_3)
+
#endif /* __ASSEMBLY__ */

#define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
@@ -108,6 +124,13 @@
__ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1), \
new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2))

+#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
+ new_c_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
+ new_c_3, vendor_id_3, errata_id_3, CONFIG_k_3) \
+ __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1), \
+ new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2), \
+ new_c_3, vendor_id_3, errata_id_3, IS_ENABLED(CONFIG_k_3))
+
#else /* CONFIG_RISCV_ALTERNATIVE */
#ifdef __ASSEMBLY__

@@ -152,15 +175,28 @@
_ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k)

/*
- * A vendor wants to replace an old_content, but another vendor has used
- * ALTERNATIVE() to patch its customized content at the same location. In
- * this case, this vendor can create a new macro ALTERNATIVE_2() based
- * on the following sample code and then replace ALTERNATIVE() with
- * ALTERNATIVE_2() to append its customized content.
+ * ALTERNATIVE_x macros allow providing multiple replacement options
+ * for an ALTERNATIVE code section. This is helpful if multiple
+ * implementation variants for the same functionality exist for
+ * different cpu cores.
+ *
+ * Usage:
+ * ALTERNATIVE_x(old_content,
+ * new_content1, vendor_id1, errata_id1, CONFIG_k1,
+ * new_content2, vendor_id2, errata_id2, CONFIG_k2,
+ * ...
+ * new_contentx, vendor_idx, errata_idx, CONFIG_kx)
*/
#define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2) \
_ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2)

+#define ALTERNATIVE_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
+ new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
+ new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3) \
+ _ALTERNATIVE_CFG_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
+ new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
+ new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3)
+
#endif
--
2.25.1