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lib: Optimize unpriv load/store implementation

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This patch optimize unpriv load/store implementation by having
dedicated unpriv trap handler (just like KVM RISC-V).

As a result of this optimization:
1. We have reduced roughly 13+ instruction in all unpriv load/store
   functions. The reduced instruction also include two function calls.
2. Per-HART trap info pointer in scratch space is now redundant
   hence removed.
3. The sbi_trap_handler() is now much cleaner because we don't have
   to handle unpriv load/store traps.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Anup Patel
2020-03-19 17:13:16 +05:30
committed by Anup Patel
parent 160c88535f
commit 1de66d170e
7 changed files with 147 additions and 125 deletions
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36
lib/sbi/sbi_hart.c
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@@ -17,6 +17,11 @@
#include <sbi/sbi_hart.h>
#include <sbi/sbi_platform.h>
extern void __sbi_unpriv_trap(void);
extern void __sbi_unpriv_trap_hext(void);
void (*sbi_hart_unpriv_trap)(void) = &__sbi_unpriv_trap;
static void mstatus_init(struct sbi_scratch *scratch, u32 hartid)
{
const struct sbi_platform *plat = sbi_platform_ptr(scratch);
@@ -203,17 +208,13 @@ static int pmp_init(struct sbi_scratch *scratch, u32 hartid)
return 0;
}
static unsigned long trap_info_offset;
int sbi_hart_init(struct sbi_scratch *scratch, u32 hartid, bool cold_boot)
{
int rc;
if (cold_boot) {
trap_info_offset = sbi_scratch_alloc_offset(__SIZEOF_POINTER__,
"HART_TRAP_INFO");
if (!trap_info_offset)
return SBI_ENOMEM;
if (misa_extension('H'))
sbi_hart_unpriv_trap = &__sbi_unpriv_trap_hext;
}
mstatus_init(scratch, hartid);
@@ -229,29 +230,6 @@ int sbi_hart_init(struct sbi_scratch *scratch, u32 hartid, bool cold_boot)
return pmp_init(scratch, hartid);
}
void *sbi_hart_get_trap_info(struct sbi_scratch *scratch)
{
unsigned long *trap_info;
if (!trap_info_offset)
return NULL;
trap_info = sbi_scratch_offset_ptr(scratch, trap_info_offset);
return (void *)(*trap_info);
}
void sbi_hart_set_trap_info(struct sbi_scratch *scratch, void *data)
{
unsigned long *trap_info;
if (!trap_info_offset)
return;
trap_info = sbi_scratch_offset_ptr(scratch, trap_info_offset);
*trap_info = (unsigned long)data;
}
void __attribute__((noreturn)) sbi_hart_hang(void)
{
while (1)