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lib: Introduce bitmap to track HARTs waiting for coldboot

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On QEMU Virt, max supported HARTs are 8 but number of HARTs
actually depend on "-smp" command-line parameter passed to
QEMU. This creates problems in sbi_hart_wake_coldboot_harts()
because when number of HARTs are less than 8.

To tackle this, we introduce a bitmap to track HARTs waiting
for coldboot to finish. We wake only those HARTs who have
set their bit in coldboot bitmap.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Anup Patel 2018-12-21 10:09:33 +05:30 • committed by Anup Patel
parent b023176c17
commit 6f02b6938f
1 changed files with 16 additions and 5 deletions
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21
lib/sbi_hart.c
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@ -263,7 +263,9 @@ struct sbi_scratch *sbi_hart_id_to_scratch(struct sbi_scratch *scratch,
return ((h2s)scratch->hartid_to_scratch)(hartid);
}
#define NO_HOTPLUG_BITMAP_SIZE __riscv_xlen
#define COLDBOOT_WAIT_BITMAP_SIZE __riscv_xlen
static spinlock_t coldboot_wait_bitmap_lock = SPIN_LOCK_INITIALIZER;
static unsigned long coldboot_wait_bitmap = 0;
void sbi_hart_wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
{
@ -271,13 +273,20 @@ void sbi_hart_wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
struct sbi_platform *plat = sbi_platform_ptr(scratch);
if ((sbi_platform_hart_count(plat) <= hartid) ||
(NO_HOTPLUG_BITMAP_SIZE <= hartid))
(COLDBOOT_WAIT_BITMAP_SIZE <= hartid))
sbi_hart_hang();
do {
spin_lock(&coldboot_wait_bitmap_lock);
coldboot_wait_bitmap |= (1UL << hartid);
spin_unlock(&coldboot_wait_bitmap_lock);
wfi();
mipval = csr_read(mip);
/* Make sure the hart woke because of ipi */
} while (!(mipval && MIP_MSIP) );
spin_lock(&coldboot_wait_bitmap_lock);
coldboot_wait_bitmap &= ~(1UL << hartid);
spin_unlock(&coldboot_wait_bitmap_lock);
} while (!(mipval && MIP_MSIP));
csr_clear(mip, MIP_MSIP);
}
@ -289,7 +298,9 @@ void sbi_hart_wake_coldboot_harts(struct sbi_scratch *scratch, u32 hartid)
for(int i = 0; i < max_hart ; i++) {
/* send an IPI to every other hart */
if (i != hartid)
spin_lock(&coldboot_wait_bitmap_lock);
if ((i != hartid) && (coldboot_wait_bitmap & (1UL << i)))
sbi_platform_ipi_inject(plat, i, hartid);
spin_unlock(&coldboot_wait_bitmap_lock);
}
}