[v2,2/8] RISC-V: Move cpuid to hartid mapping to SMP.

Commit Message

Atish Patra Jan. 8, 2019, 9:38 a.m. UTC

Currently, logical CPU id to physical hartid mapping is
defined for both smp and non-smp configurations. This
is not required as we need this only for smp configuration.
The mapping function can define directly boot_cpu_hartid
for non-smp use case.

The reverse mapping function i.e. hartid to cpuid can be called
for any valid but not booted harts. So it should return default
cpu 0 only if it is a boot hartid.

Signed-off-by: Atish Patra <[e-mail]>
Reviewed-by: Anup Patel <[e-mail]>
---
 arch/riscv/include/asm/smp.h | 15 ++++++++++++---
 arch/riscv/kernel/setup.c    |  9 ---------
 arch/riscv/kernel/smp.c      |  9 +++++++++
 3 files changed, 21 insertions(+), 12 deletions(-)

Comments

Christoph Hellwig Jan. 15, 2019, 1:52 p.m. UTC | #1

> +	if (hartid == boot_cpu_hartid)
> +		return 0;
> +	else
> +		return -1;

No need for an else after a return statement.

> +}
> +static inline unsigned long cpuid_to_hartid_map(int cpu)
> +{
> +
> +	return boot_cpu_hartid;

spurious empty line above.

Atish Patra Jan. 18, 2019, 2:08 a.m. UTC | #2

On 1/15/19 5:52 AM, Christoph Hellwig wrote:
>> +	if (hartid == boot_cpu_hartid)
>> +		return 0;
>> +	else
>> +		return -1;
> 
> No need for an else after a return statement.
>

Correct. Will update it.

>> +}
>> +static inline unsigned long cpuid_to_hartid_map(int cpu)
>> +{
>> +
>> +	return boot_cpu_hartid;
> 
> spurious empty line above.
> 
Sorry for that. Will fix it.

Regards,
Atish

Patch

diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 41aa73b4..8f30300f 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -22,12 +22,13 @@ 
 /*
  * Mapping between linux logical cpu index and hartid.
  */
-extern unsigned long __cpuid_to_hartid_map[NR_CPUS];
-#define cpuid_to_hartid_map(cpu)    __cpuid_to_hartid_map[cpu]
 
+extern unsigned long boot_cpu_hartid;
 struct seq_file;
 
 #ifdef CONFIG_SMP
+extern unsigned long __cpuid_to_hartid_map[NR_CPUS];
+#define cpuid_to_hartid_map(cpu)    __cpuid_to_hartid_map[cpu]
 
 /* print IPI stats */
 void show_ipi_stats(struct seq_file *p, int prec);
@@ -58,7 +59,15 @@  static inline void show_ipi_stats(struct seq_file *p, int prec)
 
 static inline int riscv_hartid_to_cpuid(int hartid)
 {
-	return 0;
+	if (hartid == boot_cpu_hartid)
+		return 0;
+	else
+		return -1;
+}
+static inline unsigned long cpuid_to_hartid_map(int cpu)
+{
+
+	return boot_cpu_hartid;
 }
 
 static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index fc8006a0..f377add4 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -61,15 +61,6 @@  EXPORT_SYMBOL(empty_zero_page);
 atomic_t hart_lottery;
 unsigned long boot_cpu_hartid;
 
-unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
-	[0 ... NR_CPUS-1] = INVALID_HARTID
-};
-
-void __init smp_setup_processor_id(void)
-{
-	cpuid_to_hartid_map(0) = boot_cpu_hartid;
-}
-
 #ifdef CONFIG_BLK_DEV_INITRD
 static void __init setup_initrd(void)
 {
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 57b1383e..e407bd4f 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -34,6 +34,15 @@  enum ipi_message_type {
 	IPI_MAX
 };
 
+unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
+	[0 ... NR_CPUS-1] = INVALID_HARTID
+};
+
+void __init smp_setup_processor_id(void)
+{
+	cpuid_to_hartid_map(0) = boot_cpu_hartid;
+}
+
 /* A collection of single bit ipi messages.  */
 static struct {
 	unsigned long stats[IPI_MAX] ____cacheline_aligned;