Revert "src/arch/x86: Use core apic id to get cpu_index()"

This reverts commit 095c931cf12924da9011b47aa64f4a6f11d89f13.

Previously cpu_info() was implemented with a struct on top of an
aligned stack. As FSP changed the stack value cpu_info() could not be
used in FSP context (which PPI is). Now cpu_info() uses GDT segments,
which FSP does not touch so it can be used.

This also exports cpu_infos from cpu.c as it's a convenient way to get
the struct device * for a certain index.

TESTED on aldrvp: FSP-S works and is able to run code on APs.

Change-Id: I3a40156ba275b572d7d1913d8c17c24b4c8f6d78
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69509
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 8 insertions, 39 deletions

diff --git a/src/arch/x86/cpu.c b/src/arch/x86/cpu.c
index 9fc52330dc..face248fc2 100644
--- a/src/arch/x86/cpu.c
+++ b/src/arch/x86/cpu.c
@@ -318,33 +318,9 @@ void arch_bootstate_coreboot_exit(void)
 	mp_park_aps();
 }
 
-/*
- * Previously cpu_index() implementation assumes that cpu_index()
- * function will always getting called from coreboot context
- * (ESP stack pointer will always refer to coreboot).
- *
- * But with MP_SERVICES_PPI implementation in coreboot this
- * assumption might not be true, where FSP context (stack pointer refers
- * to FSP) will request to get cpu_index().
- *
- * Hence new logic to use cpuid to fetch lapic id and matches with
- * cpus_default_apic_id[] variable to return correct cpu_index().
- */
-int cpu_index(void)
-{
-	int i;
-	int lapic_id = initial_lapicid();
-
-	for (i = 0; i < CONFIG_MAX_CPUS; i++) {
-		if (cpu_get_apic_id(i) == lapic_id)
-			return i;
-	}
-	return -1;
-}
-
 /* cpu_info() looks at address 0 at the base of %gs for a pointer to struct cpu_info */
 static struct per_cpu_segment_data segment_data[CONFIG_MAX_CPUS];
-static struct cpu_info cpu_infos[CONFIG_MAX_CPUS];
+struct cpu_info cpu_infos[CONFIG_MAX_CPUS];
 
 enum cb_err set_cpu_info(unsigned int index, struct device *cpu)
 {
diff --git a/src/arch/x86/include/arch/cpu.h b/src/arch/x86/include/arch/cpu.h
index c7c6b4e074..18bc961828 100644
--- a/src/arch/x86/include/arch/cpu.h
+++ b/src/arch/x86/include/arch/cpu.h
@@ -161,6 +161,13 @@ static inline struct cpu_info *cpu_info(void)
 	return ci;
 }
 
+static inline unsigned long cpu_index(void)
+{
+	struct cpu_info *ci;
+	ci = cpu_info();
+	return ci->index;
+}
+
 struct cpuinfo_x86 {
 	uint8_t	x86;		/* CPU family */
 	uint8_t	x86_vendor;	/* CPU vendor */
@@ -212,20 +219,6 @@ uint32_t cpu_get_feature_flags_ecx(void);
  */
 uint32_t cpu_get_feature_flags_edx(void);
 
-/*
- * Previously cpu_index() implementation assumes that cpu_index()
- * function will always getting called from coreboot context
- * (ESP stack pointer will always refer to coreboot).
- *
- * But with MP_SERVICES_PPI implementation in coreboot this
- * assumption might not be true, where FSP context (stack pointer refers
- * to FSP) will request to get cpu_index().
- *
- * Hence new logic to use cpuid to fetch lapic id and matches with
- * cpus_default_apic_id[] variable to return correct cpu_index().
- */
-int cpu_index(void);
-
 #define DETERMINISTIC_CACHE_PARAMETERS_CPUID_IA	0x04
 #define DETERMINISTIC_CACHE_PARAMETERS_CPUID_AMD	0x8000001d