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| author | Nathan Lynch <nathanl@linux.ibm.com> | 2020-12-08 00:51:35 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-08 13:40:54 +0300 |
| commit | 7049b288ea8c95f270ec8fe643e3c3187938d5af (patch) | |
| tree | 1198b3b4d30b439342b521dd4a657245251b844f /arch/powerpc/kernel/rtas.c | |
| parent | 970e453ea4ecdd7a16a46c229294547148d1c7b6 (diff) | |
| download | linux-7049b288ea8c95f270ec8fe643e3c3187938d5af.tar.xz | |
powerpc/rtas: rtas_ibm_suspend_me -> rtas_ibm_suspend_me_unsafe
The pseries partition suspend sequence requires that all active CPUs
call H_JOIN, which suspends all but one of them with interrupts
disabled. The "chosen" CPU is then to call ibm,suspend-me to complete
the suspend. Upon returning from ibm,suspend-me, the chosen CPU is to
use H_PROD to wake the joined CPUs.
Using on_each_cpu() for this, as rtas_ibm_suspend_me() does to
implement partition migration, is susceptible to deadlock with other
users of on_each_cpu() and with users of stop_machine APIs. The
callback passed to on_each_cpu() is not allowed to synchronize with
other CPUs in the way it is used here.
Complicating the fix is the fact that rtas_ibm_suspend_me() also
occupies the function name that should be used to provide a more
conventional wrapper for ibm,suspend-me. Rename rtas_ibm_suspend_me()
to rtas_ibm_suspend_me_unsafe() to free up the name and indicate that
it should not gain users.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-4-nathanl@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/rtas.c')
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 4ed64aba37d6..0a8e5dc2c108 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -843,7 +843,7 @@ static void rtas_percpu_suspend_me(void *info) __rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1); } -int rtas_ibm_suspend_me(u64 handle) +int rtas_ibm_suspend_me_unsafe(u64 handle) { long state; long rc; @@ -949,7 +949,7 @@ int rtas_call_reentrant(int token, int nargs, int nret, int *outputs, ...) } #else /* CONFIG_PPC_PSERIES */ -int rtas_ibm_suspend_me(u64 handle) +int rtas_ibm_suspend_me_unsafe(u64 handle) { return -ENOSYS; } @@ -1185,7 +1185,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs) int rc = 0; u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32) | be32_to_cpu(args.args[1]); - rc = rtas_ibm_suspend_me(handle); + rc = rtas_ibm_suspend_me_unsafe(handle); if (rc == -EAGAIN) args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE); else if (rc == -EIO) |