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Subject[PATCH v3 11/13] MIPS: mm: Simplify build_update_entries
Date
We can simplify build_update_entries by unifying the code for the 36 bit
physical addressing with MIPS32 case with the general case, by using
pte_off_ variables in all cases & handling the trivial
_PAGE_GLOBAL_SHIFT == 0 case in build_convert_pte_to_entrylo. This
leaves XPA as the only special case.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>

---

Changes in v3: None
Changes in v2:
- #ifdef on CONFIG_CPU_MIPS32 instead of config_enabled(CONFIG_32BIT) to avoid referencing pte_high in configurations where it doesn't exist.

arch/mips/mm/tlbex.c | 37 ++++++++++++++++---------------------
1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 0bd3755..c7c14bd 100644
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -626,6 +626,11 @@ static void build_tlb_write_entry(u32 **p, struct uasm_label **l,
static __maybe_unused void build_convert_pte_to_entrylo(u32 **p,
unsigned int reg)
{
+ if (_PAGE_GLOBAL_SHIFT == 0) {
+ /* pte_t is already in EntryLo format */
+ return;
+ }
+
if (cpu_has_rixi && _PAGE_NO_EXEC) {
if (fill_includes_sw_bits) {
UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL));
@@ -1003,10 +1008,16 @@ static void build_get_ptep(u32 **p, unsigned int tmp, unsigned int ptr)

static void build_update_entries(u32 **p, unsigned int tmp, unsigned int ptep)
{
- if (config_enabled(CONFIG_XPA)) {
- int pte_off_even = sizeof(pte_t) / 2;
- int pte_off_odd = pte_off_even + sizeof(pte_t);
+ int pte_off_even = 0;
+ int pte_off_odd = sizeof(pte_t);

+#if defined(CONFIG_CPU_MIPS32) && defined(CONFIG_PHYS_ADDR_T_64BIT)
+ /* The low 32 bits of EntryLo is stored in pte_high */
+ pte_off_even += offsetof(pte_t, pte_high);
+ pte_off_odd += offsetof(pte_t, pte_high);
+#endif
+
+ if (config_enabled(CONFIG_XPA)) {
uasm_i_lw(p, tmp, pte_off_even, ptep); /* even pte */
UASM_i_ROTR(p, tmp, tmp, ilog2(_PAGE_GLOBAL));
UASM_i_MTC0(p, tmp, C0_ENTRYLO0);
@@ -1025,24 +1036,8 @@ static void build_update_entries(u32 **p, unsigned int tmp, unsigned int ptep)
return;
}

- /*
- * 64bit address support (36bit on a 32bit CPU) in a 32bit
- * Kernel is a special case. Only a few CPUs use it.
- */
- if (config_enabled(CONFIG_PHYS_ADDR_T_64BIT) && !cpu_has_64bits) {
- int pte_off_even = sizeof(pte_t) / 2;
- int pte_off_odd = pte_off_even + sizeof(pte_t);
-
- uasm_i_lw(p, tmp, pte_off_even, ptep); /* even pte */
- UASM_i_MTC0(p, tmp, C0_ENTRYLO0);
-
- uasm_i_lw(p, ptep, pte_off_odd, ptep); /* odd pte */
- UASM_i_MTC0(p, ptep, C0_ENTRYLO1);
- return;
- }
-
- UASM_i_LW(p, tmp, 0, ptep); /* get even pte */
- UASM_i_LW(p, ptep, sizeof(pte_t), ptep); /* get odd pte */
+ UASM_i_LW(p, tmp, pte_off_even, ptep); /* get even pte */
+ UASM_i_LW(p, ptep, pte_off_odd, ptep); /* get odd pte */
if (r45k_bvahwbug())
build_tlb_probe_entry(p);
build_convert_pte_to_entrylo(p, tmp);
--
2.8.0
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