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lib: sbi: Wakeup non-coldboot HARTs early in the coldboot path

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Currently, all non-coldboot HARTs busy spin in wait_for_coldboot()
until the entire coldboot init sequence is completed.

This means:
1) On QEMU, all non-coldboot HARTs will eat host CPU time and
   also slow down the coldboot HART until the entire coldboot
   init sequence is completed.
2) On real HW, all non-coldboot HARTs will consume more CPU
   power until the entire coldboot init sequence is completed.

To address this, wake up all non-coldboot HARTs as early as
possible in the coldboot init sequence.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
This commit is contained in:
Anup Patel
2024-03-19 17:56:24 +05:30
committed by Anup Patel
parent beb0cd177f
commit 7862c244bc
1 changed files with 9 additions and 2 deletions
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11
lib/sbi/sbi_init.c
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@@ -244,6 +244,14 @@ static void __noreturn init_coldboot(struct sbi_scratch *scratch, u32 hartid)
if (rc) if (rc)
sbi_hart_hang(); sbi_hart_hang();
/*
* All non-coldboot HARTs do HSM initialization (i.e. enter HSM state
* machine) at the start of the warmboot path so it is wasteful to
* have these HARTs busy spin in wait_for_coldboot() until coldboot
* path is completed.
*/
wake_coldboot_harts(scratch, hartid);
rc = sbi_platform_early_init(plat, true); rc = sbi_platform_early_init(plat, true);
if (rc) if (rc)
sbi_hart_hang(); sbi_hart_hang();
@@ -355,8 +363,6 @@ static void __noreturn init_coldboot(struct sbi_scratch *scratch, u32 hartid)
sbi_hart_hang(); sbi_hart_hang();
} }
wake_coldboot_harts(scratch, hartid);
count = sbi_scratch_offset_ptr(scratch, init_count_offset); count = sbi_scratch_offset_ptr(scratch, init_count_offset);
(*count)++; (*count)++;
@@ -376,6 +382,7 @@ static void __noreturn init_warm_startup(struct sbi_scratch *scratch,
count = sbi_scratch_offset_ptr(scratch, entry_count_offset); count = sbi_scratch_offset_ptr(scratch, entry_count_offset);
(*count)++; (*count)++;
/* Note: This has to be first thing in warmboot init sequence */
rc = sbi_hsm_init(scratch, hartid, false); rc = sbi_hsm_init(scratch, hartid, false);
if (rc) if (rc)
sbi_hart_hang(); sbi_hart_hang();