sys_rtas() cannot call ibm,suspend-me directly in the same way it
handles other inputs. Instead it must dispatch the request to code
that can first perform the H_JOIN sequence before any call to
ibm,suspend-me can succeed. Over time kernel/rtas.c has accreted a fair
amount of platform-specific code to implement this.
Since a different, more robust implementation of the suspend sequence
is now in the pseries platform code, we want to dispatch the request
there while minimizing additional dependence on pseries.
Use a weak function that only pseries overrides. Note that invoking
ibm,suspend-me via the RTAS syscall is all but deprecated; this change
preserves ABI compatibility for old programs while providing to them
the benefit of the new partition suspend implementation. This is a
behavior change in that the kernel performs the device tree update and
firmware activation before returning, but experimentation indicates
this is tolerated fine by legacy user space.
Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
---
arch/powerpc/include/asm/rtas.h | 1 +
arch/powerpc/kernel/rtas.c | 8 +++++++-
arch/powerpc/platforms/pseries/mobility.c | 5 +++++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
index fdefe6a974eb..be0fc2536673 100644
--- a/arch/powerpc/include/asm/rtas.h
+++ b/arch/powerpc/include/asm/rtas.h
@@ -260,6 +260,7 @@ extern int rtas_suspend_cpu(struct rtas_suspend_me_data
*data);
extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
int rtas_ibm_suspend_me_unsafe(u64 handle);
int rtas_ibm_suspend_me(int *fw_status);
+int rtas_syscall_dispatch_ibm_suspend_me(u64 handle);
struct rtc_time;
extern time64_t rtas_get_boot_time(void);
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 58bbd69a233f..52fb394f15d6 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1221,6 +1221,12 @@ static bool block_rtas_call(int token, int nargs,
#endif /* CONFIG_PPC_RTAS_FILTER */
+/* Only pseries should need to override this. */
+int __weak rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
+{
+ return -EINVAL;
+}
+
/* We assume to be passed big endian arguments */
SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
{
@@ -1271,7 +1277,7 @@ 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_unsafe(handle);
+ rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
if (rc == -EAGAIN)
args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
else if (rc == -EIO)
diff --git a/arch/powerpc/platforms/pseries/mobility.c
b/arch/powerpc/platforms/pseries/mobility.c
index e459cdb8286f..d6417c9db201 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -622,6 +622,11 @@ static int pseries_migrate_partition(u64 handle)
return ret;
}
+int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
+{
+ return pseries_migrate_partition(handle);
+}
+
static ssize_t migration_store(struct class *class,
struct class_attribute *attr, const char *buf,
size_t count)
--
2.25.4
