[PATCH 05/20] ARC: boot log: eliminate struct cpuinfo_arc #1: mm

Vineet Gupta
2023-08-15T00:48:58Z

This is first step in eliminating struct cpuinfo_arc[NR_CPUS]

Back when we had just ARCompact ISA, the idea was to read/bit-fiddle
the BCRs once and and cache decoded information in a global struct ready
to use.

With ARCv2 it was modified to contained abstract / ISA agnostic
information.

However with ARCv3 there 's too much disparity to abstract in common
structures. So drop the entire decode once and store paradigm. Afterall
there's only 2 users of this machinery anyways: boot printing and
cat /proc/cpuinfo. None is performance critical to warrant locking away
resident memory per cpu.

This patch is first step in that direction
- decouples struct cpuinfo_arc_mmu from global struct cpuinfo_arc
- mmu code still has a trimmed down static version of
struct cpuinfo_arc_mmu to cache information needed in performance
critical code such as tlb flush routines
- folds read_decode_mmu_bcr() into arc_mmu_mumbojumbo()
- setup_processor() directly calls arc_mmu_init() and not via
arc_cpu_init()

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
---
arch/arc/include/asm/arcregs.h | 27 +++++++---
arch/arc/include/asm/setup.h | 1 -
arch/arc/kernel/setup.c | 4 +-
arch/arc/mm/tlb.c | 92 +++++++++++++---------------------
4 files changed, 57 insertions(+), 67 deletions(-)

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 2162023195c5..af00cbe9b850 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -185,6 +185,27 @@ struct bcr_uarch_build_arcv2 {
#endif
};

+struct bcr_mmu_3 {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
+ u_itlb:4, u_dtlb:4;
+#else
+ unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
+ ways:4, ver:8;
+#endif
+};
+
+struct bcr_mmu_4 {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
+ n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
+#else
+ /* DTLB ITLB JES JE JA */
+ unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
+ pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
+#endif
+};
+
struct bcr_mpy {
#ifdef CONFIG_CPU_BIG_ENDIAN
unsigned int pad:8, x1616:8, dsp:4, cycles:2, type:2, ver:8;
@@ -307,11 +328,6 @@ struct bcr_generic {
* Generic structures to hold build configuration used at runtime
*/

-struct cpuinfo_arc_mmu {
- unsigned int ver:4, pg_sz_k:8, s_pg_sz_m:8, pad:10, sasid:1, pae:1;
- unsigned int sets:12, ways:4, u_dtlb:8, u_itlb:8;
-};
-
struct cpuinfo_arc_cache {
unsigned int sz_k:14, line_len:8, assoc:4, alias:1, vipt:1, pad:4;
};
@@ -326,7 +342,6 @@ struct cpuinfo_arc_ccm {

struct cpuinfo_arc {
struct cpuinfo_arc_cache icache, dcache, slc;
- struct cpuinfo_arc_mmu mmu;
struct cpuinfo_arc_bpu bpu;
struct bcr_identity core;
struct bcr_isa_arcv2 isa;
diff --git a/arch/arc/include/asm/setup.h b/arch/arc/include/asm/setup.h
index 374138832c5a..76443f198778 100644
--- a/arch/arc/include/asm/setup.h
+++ b/arch/arc/include/asm/setup.h
@@ -36,7 +36,6 @@ long __init arc_get_mem_sz(void);

extern void arc_mmu_init(void);
extern char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
-extern void read_decode_mmu_bcr(void);

extern void arc_cache_init(void);
extern char *arc_cache_mumbojumbo(int cpu_id, char *buf, int len);
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 41f07b3e594e..094461540f8a 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -186,7 +186,6 @@ static void read_arc_build_cfg_regs(void)
/* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
read_decode_ccm_bcr(cpu);

- read_decode_mmu_bcr();
read_decode_cache_bcr();

if (is_isa_arcompact()) {
@@ -256,7 +255,7 @@ static void read_arc_build_cfg_regs(void)
cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);

/* there's no direct way to distinguish 750 vs. 770 */
- if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
+ if (unlikely(cpu->core.family < 0x34))
cpu->name = "ARC750";
} else {
cpu->isa = isa;
@@ -463,6 +462,7 @@ void setup_processor(void)
arc_init_IRQ();

pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
+ pr_info("%s", arc_mmu_mumbojumbo(cpu_id, str, sizeof(str)));

arc_mmu_init();
arc_cache_init();
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 2a3105a682c3..17e32c707367 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -18,7 +18,9 @@
/* A copy of the ASID from the PID reg is kept in asid_cache */
DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;

-static int __read_mostly pae_exists;
+static struct cpuinfo_arc_mmu {
+ unsigned int ver, pg_sz_k, s_pg_sz_m, pae, sets, ways;
+} mmuinfo;

/*
* Utility Routine to erase a J-TLB entry
@@ -131,7 +133,7 @@ static void tlb_entry_insert(unsigned int pd0, phys_addr_t pd1)

noinline void local_flush_tlb_all(void)
{
- struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
+ struct cpuinfo_arc_mmu *mmu = &mmuinfo;
unsigned long flags;
unsigned int entry;
int num_tlb = mmu->sets * mmu->ways;
@@ -560,89 +562,63 @@ void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
* the cpuinfo structure for later use.
* No Validation is done here, simply read/convert the BCRs
*/
-void read_decode_mmu_bcr(void)
+char *arc_mmu_mumbojumbo(int c, char *buf, int len)
{
- struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
- unsigned int tmp;
- struct bcr_mmu_3 {
-#ifdef CONFIG_CPU_BIG_ENDIAN
- unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
- u_itlb:4, u_dtlb:4;
-#else
- unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
- ways:4, ver:8;
-#endif
- } *mmu3;
-
- struct bcr_mmu_4 {
-#ifdef CONFIG_CPU_BIG_ENDIAN
- unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
- n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
-#else
- /* DTLB ITLB JES JE JA */
- unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
- pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
-#endif
- } *mmu4;
+ struct cpuinfo_arc_mmu *mmu = &mmuinfo;
+ unsigned int bcr, u_dtlb, u_itlb, sasid;
+ struct bcr_mmu_3 *mmu3;
+ struct bcr_mmu_4 *mmu4;
+ char super_pg[64] = "";
+ int n = 0;

- tmp = read_aux_reg(ARC_REG_MMU_BCR);
- mmu->ver = (tmp >> 24);
+ bcr = read_aux_reg(ARC_REG_MMU_BCR);
+ mmu->ver = (bcr >> 24);

if (is_isa_arcompact() && mmu->ver == 3) {
- mmu3 = (struct bcr_mmu_3 *)&tmp;
+ mmu3 = (struct bcr_mmu_3 *)&bcr;
mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
mmu->sets = 1 << mmu3->sets;
mmu->ways = 1 << mmu3->ways;
- mmu->u_dtlb = mmu3->u_dtlb;
- mmu->u_itlb = mmu3->u_itlb;
- mmu->sasid = mmu3->sasid;
+ u_dtlb = mmu3->u_dtlb;
+ u_itlb = mmu3->u_itlb;
+ sasid = mmu3->sasid;
} else {
- mmu4 = (struct bcr_mmu_4 *)&tmp;
+ mmu4 = (struct bcr_mmu_4 *)&bcr;
mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11);
mmu->sets = 64 << mmu4->n_entry;
mmu->ways = mmu4->n_ways * 2;
- mmu->u_dtlb = mmu4->u_dtlb * 4;
- mmu->u_itlb = mmu4->u_itlb * 4;
- mmu->sasid = mmu4->sasid;
- pae_exists = mmu->pae = mmu4->pae;
+ u_dtlb = mmu4->u_dtlb * 4;
+ u_itlb = mmu4->u_itlb * 4;
+ sasid = mmu4->sasid;
+ mmu->pae = mmu4->pae;
}
-}

-char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
-{
- int n = 0;
- struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu;
- char super_pg[64] = "";
-
- if (p_mmu->s_pg_sz_m)
- scnprintf(super_pg, 64, "%dM Super Page %s",
- p_mmu->s_pg_sz_m,
- IS_USED_CFG(CONFIG_TRANSPARENT_HUGEPAGE));
+ if (mmu->s_pg_sz_m)
+ scnprintf(super_pg, 64, "/%dM%s",
+ mmu->s_pg_sz_m,
+ IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) ? " (THP enabled)":"");

n += scnprintf(buf + n, len - n,
- "MMU [v%x]\t: %dk PAGE, %s, swalk %d lvl, JTLB %d (%dx%d), uDTLB %d, uITLB %d%s%s\n",
- p_mmu->ver, p_mmu->pg_sz_k, super_pg, CONFIG_PGTABLE_LEVELS,
- p_mmu->sets * p_mmu->ways, p_mmu->sets, p_mmu->ways,
- p_mmu->u_dtlb, p_mmu->u_itlb,
- IS_AVAIL2(p_mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));
+ "MMU [v%x]\t: %dk%s, swalk %d lvl, JTLB %dx%d, uDTLB %d, uITLB %d%s%s\n",
+ mmu->ver, mmu->pg_sz_k, super_pg, CONFIG_PGTABLE_LEVELS,
+ mmu->sets, mmu->ways,
+ u_dtlb, u_itlb,
+ IS_AVAIL2(mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));

return buf;
}

int pae40_exist_but_not_enab(void)
{
- return pae_exists && !is_pae40_enabled();
+ return mmuinfo.pae && !is_pae40_enabled();
}

void arc_mmu_init(void)
{
- struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
- char str[256];
+ struct cpuinfo_arc_mmu *mmu = &mmuinfo;
int compat = 0;

- pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
-
/*
* Can't be done in processor.h due to header include dependencies
*/
@@ -719,7 +695,7 @@ volatile int dup_pd_silent; /* Be silent abt it or complain (default) */
void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
struct pt_regs *regs)
{
- struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
+ struct cpuinfo_arc_mmu *mmu = &mmuinfo;
unsigned long flags;
int set, n_ways = mmu->ways;

--
2.34.1