[PATCH v5 03/14] riscv: allow different stages with alternatives

Heiko Stuebner
2022-01-21T16:37:31Z

Future features may need to be applied at a different
time during boot, so allow defining stages for alternatives
and handling them differently depending on the stage.

Also make the alternatives-location more flexible so that
future stages may provide their own location.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
arch/riscv/errata/sifive/errata.c | 3 ++-
arch/riscv/include/asm/alternative.h | 5 ++++-
arch/riscv/kernel/alternative.c | 25 +++++++++++++++++--------
3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c
index f5e5ae70e829..4fe03ac41fd7 100644
--- a/arch/riscv/errata/sifive/errata.c
+++ b/arch/riscv/errata/sifive/errata.c
@@ -80,7 +80,8 @@ static void __init warn_miss_errata(u32 miss_errata)
}

void __init sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
- unsigned long archid, unsigned long impid)
+ unsigned long archid, unsigned long impid,
+ unsigned int stage)
{
struct alt_entry *alt;
u32 cpu_req_errata = sifive_errata_probe(archid, impid);
diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h
index e625d3cafbed..811bdd8027db 100644
--- a/arch/riscv/include/asm/alternative.h
+++ b/arch/riscv/include/asm/alternative.h
@@ -17,6 +17,8 @@
#include <linux/stddef.h>
#include <asm/hwcap.h>

+#define RISCV_ALTERNATIVES_BOOT 0 /* alternatives applied during regular boot */
+
void __init apply_boot_alternatives(void);

struct alt_entry {
@@ -33,7 +35,8 @@ struct errata_checkfunc_id {
};

void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
- unsigned long archid, unsigned long impid);
+ unsigned long archid, unsigned long impid,
+ unsigned int stage);

#endif
#endif
diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c
index 3b15885db70b..ead00c508266 100644
--- a/arch/riscv/kernel/alternative.c
+++ b/arch/riscv/kernel/alternative.c
@@ -22,7 +22,8 @@ static struct cpu_manufacturer_info_t {
} cpu_mfr_info;

static void (*vendor_patch_func)(struct alt_entry *begin, struct alt_entry *end,
- unsigned long archid, unsigned long impid);
+ unsigned long archid, unsigned long impid,
+ unsigned int stage);

static inline void __init riscv_fill_cpu_mfr_info(void)
{
@@ -57,6 +58,18 @@ static void __init init_alternative(void)
* a feature detect on the boot CPU). No need to worry about other CPUs
* here.
*/
+static void __init _apply_alternatives(struct alt_entry *begin,
+ struct alt_entry *end,
+ unsigned int stage)
+{
+ if (!vendor_patch_func)
+ return;
+
+ vendor_patch_func(begin, end,
+ cpu_mfr_info.arch_id, cpu_mfr_info.imp_id,
+ stage);
+}
+
void __init apply_boot_alternatives(void)
{
/* If called on non-boot cpu things could go wrong */
@@ -64,11 +77,7 @@ void __init apply_boot_alternatives(void)

init_alternative();

- if (!vendor_patch_func)
- return;
-
- vendor_patch_func((struct alt_entry *)__alt_start,
- (struct alt_entry *)__alt_end,
- cpu_mfr_info.arch_id, cpu_mfr_info.imp_id);
+ _apply_alternatives((struct alt_entry *)__alt_start,
+ (struct alt_entry *)__alt_end,
+ RISCV_ALTERNATIVES_BOOT);
}
-
--
2.30.2