riscv: allow different stages with alternatives
From: Heiko Stuebner <heiko@...> Date: Fri, 17 Dec 2021 00:08:35 +0100
Commit-Message
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. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
arch/riscv/errata/sifive/errata.c | 3 ++- arch/riscv/include/asm/alternative.h | 5 ++++- arch/riscv/kernel/alternative.c | 22 ++++++++++++++-------- 3 files changed, 20 insertions(+), 10 deletions(-)
Statistics
- 20 lines added
- 10 lines removed
Changes
---------------------- arch/riscv/errata/sifive/errata.c -----------------------
index f5e5ae70e829..4fe03ac41fd7 100644
@@ -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 int stage)
{
struct alt_entry *alt;
u32 cpu_req_errata = sifive_errata_probe(archid, impid);
--------------------- arch/riscv/include/asm/alternative.h ---------------------
index e625d3cafbed..811bdd8027db 100644
@@ -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 int stage);
#endif
#endif
----------------------- arch/riscv/kernel/alternative.c ------------------------
index 3b15885db70b..416e7a380ee4 100644
@@ -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 int stage);
static inline void __init riscv_fill_cpu_mfr_info(void)
{
@@ -57,18 +58,23 @@ 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(unsigned int stage)
{
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,
+ stage);
}
+void __init apply_boot_alternatives(void)
+{
+ /* If called on non-boot cpu things could go wrong */
+ WARN_ON(smp_processor_id() != 0);
+
+ init_alternative();
+
+ _apply_alternatives(RISCV_ALTERNATIVES_BOOT);
+}