[PATCH v2] powerpc/64s: Get LPID bit width from device tree

[PATCH v2] powerpc/64s: Get LPID bit width from device tree

[Nicholas Piggin]

Allow the LPID bit width and partition table size to be set at runtime
from the device tree.

Move the PID bit width detection into the same place.

KVM does not support using different sizes yet, this is mainly required
to get the PTCR register values correct.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/book3s/64/mmu.h |  9 +++--
 arch/powerpc/mm/book3s64/pgtable.c       |  5 ---
 arch/powerpc/mm/book3s64/radix_pgtable.c | 13 +------
 arch/powerpc/mm/init_64.c                | 47 +++++++++++++++++++++++-
 4 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index c02f42d1031e..8c500dd6fee4 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -62,6 +62,9 @@ extern struct patb_entry *partition_tb;
 #define PRTS_MASK	0x1f		/* process table size field */
 #define PRTB_MASK	0x0ffffffffffff000UL
 
+/* Number of supported LPID bits */
+extern unsigned int mmu_lpid_bits;
+
 /* Number of supported PID bits */
 extern unsigned int mmu_pid_bits;
 
@@ -76,10 +79,8 @@ extern unsigned long __ro_after_init radix_mem_block_size;
 #define PRTB_SIZE_SHIFT	(mmu_pid_bits + 4)
 #define PRTB_ENTRIES	(1ul << mmu_pid_bits)
 
-/*
- * Power9 currently only support 64K partition table size.
- */
-#define PATB_SIZE_SHIFT	16
+#define PATB_SIZE_SHIFT	(mmu_lpid_bits + 4)
+#define PATB_ENTRIES	(1ul << mmu_lpid_bits)
 
 typedef unsigned long mm_context_id_t;
 struct spinlock;
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 9e16c7b1a6c5..13d1fbddecb9 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -207,17 +207,12 @@ void __init mmu_partition_table_init(void)
 	unsigned long patb_size = 1UL << PATB_SIZE_SHIFT;
 	unsigned long ptcr;
 
-	BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 36), "Partition table size too large.");
 	/* Initialize the Partition Table with no entries */
 	partition_tb = memblock_alloc(patb_size, patb_size);
 	if (!partition_tb)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 		      __func__, patb_size, patb_size);
 
-	/*
-	 * update partition table control register,
-	 * 64 K size.
-	 */
 	ptcr = __pa(partition_tb) | (PATB_SIZE_SHIFT - 12);
 	set_ptcr_when_no_uv(ptcr);
 	powernv_set_nmmu_ptcr(ptcr);
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index ae20add7954a..1c855434f8dc 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -33,7 +33,6 @@
 
 #include <trace/events/thp.h>
 
-unsigned int mmu_pid_bits;
 unsigned int mmu_base_pid;
 unsigned long radix_mem_block_size __ro_after_init;
 
@@ -357,18 +356,13 @@ static void __init radix_init_pgtable(void)
 						-1, PAGE_KERNEL));
 	}
 
-	/* Find out how many PID bits are supported */
 	if (!cpu_has_feature(CPU_FTR_HVMODE) &&
 			cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG)) {
 		/*
 		 * Older versions of KVM on these machines perfer if the
 		 * guest only uses the low 19 PID bits.
 		 */
-		if (!mmu_pid_bits)
-			mmu_pid_bits = 19;
-	} else {
-		if (!mmu_pid_bits)
-			mmu_pid_bits = 20;
+		mmu_pid_bits = 19;
 	}
 	mmu_base_pid = 1;
 
@@ -449,11 +443,6 @@ static int __init radix_dt_scan_page_sizes(unsigned long node,
 	if (type == NULL || strcmp(type, "cpu") != 0)
 		return 0;
 
-	/* Find MMU PID size */
-	prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
-	if (prop && size == 4)
-		mmu_pid_bits = be32_to_cpup(prop);
-
 	/* Grab page size encodings */
 	prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
 	if (!prop)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 386be136026e..04f45fcb1222 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -370,6 +370,9 @@ void register_page_bootmem_memmap(unsigned long section_nr,
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
 #ifdef CONFIG_PPC_BOOK3S_64
+unsigned int mmu_lpid_bits;
+unsigned int mmu_pid_bits;
+
 static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT);
 
 static int __init parse_disable_radix(char *p)
@@ -437,19 +440,61 @@ static void __init early_check_vec5(void)
 	}
 }
 
+static int __init dt_scan_mmu_pid_width(unsigned long node,
+					   const char *uname, int depth,
+					   void *data)
+{
+	int size = 0;
+	const __be32 *prop;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+
+	/* We are scanning "cpu" nodes only */
+	if (type == NULL || strcmp(type, "cpu") != 0)
+		return 0;
+
+	/* Find MMU LPID, PID register size */
+	prop = of_get_flat_dt_prop(node, "ibm,mmu-lpid-bits", &size);
+	if (prop && size == 4)
+		mmu_lpid_bits = be32_to_cpup(prop);
+
+	prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
+	if (prop && size == 4)
+		mmu_pid_bits = be32_to_cpup(prop);
+
+	if (!mmu_pid_bits && !mmu_lpid_bits)
+		return 0;
+
+	return 1;
+}
+
 void __init mmu_early_init_devtree(void)
 {
+	int rc;
+	bool hvmode = !!(mfmsr() & MSR_HV);
+
 	/* Disable radix mode based on kernel command line. */
 	if (disable_radix)
 		cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
 
+	rc = of_scan_flat_dt(dt_scan_mmu_pid_width, NULL);
+	if (hvmode && !mmu_lpid_bits) {
+		if (early_cpu_has_feature(CPU_FTR_ARCH_207S))
+			mmu_lpid_bits = 12; /* POWER8-10 */
+		else
+			mmu_lpid_bits = 10; /* POWER7 */
+	}
+	if (!mmu_pid_bits) {
+		if (early_cpu_has_feature(CPU_FTR_ARCH_300))
+			mmu_pid_bits = 20; /* POWER9-10 */
+	}
+
 	/*
 	 * Check /chosen/ibm,architecture-vec-5 if running as a guest.
 	 * When running bare-metal, we can use radix if we like
 	 * even though the ibm,architecture-vec-5 property created by
 	 * skiboot doesn't have the necessary bits set.
 	 */
-	if (!(mfmsr() & MSR_HV))
+	if (!hvmode)
 		early_check_vec5();
 
 	if (early_radix_enabled()) {
-- 
2.23.0

Re: [PATCH v2] powerpc/64s: Get LPID bit width from device tree

[Fabiano Rosas]

Nicholas Piggin <npiggin@gmail.com> writes:

> Allow the LPID bit width and partition table size to be set at runtime
> from the device tree.
>
> Move the PID bit width detection into the same place.
>
> KVM does not support using different sizes yet, this is mainly required
> to get the PTCR register values correct.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>

> ---
>  arch/powerpc/include/asm/book3s/64/mmu.h |  9 +++--
>  arch/powerpc/mm/book3s64/pgtable.c       |  5 ---
>  arch/powerpc/mm/book3s64/radix_pgtable.c | 13 +------
>  arch/powerpc/mm/init_64.c                | 47 +++++++++++++++++++++++-
>  4 files changed, 52 insertions(+), 22 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
> index c02f42d1031e..8c500dd6fee4 100644
> --- a/arch/powerpc/include/asm/book3s/64/mmu.h
> +++ b/arch/powerpc/include/asm/book3s/64/mmu.h
> @@ -62,6 +62,9 @@ extern struct patb_entry *partition_tb;
>  #define PRTS_MASK	0x1f		/* process table size field */
>  #define PRTB_MASK	0x0ffffffffffff000UL
>  
> +/* Number of supported LPID bits */
> +extern unsigned int mmu_lpid_bits;
> +
>  /* Number of supported PID bits */
>  extern unsigned int mmu_pid_bits;
>  
> @@ -76,10 +79,8 @@ extern unsigned long __ro_after_init radix_mem_block_size;
>  #define PRTB_SIZE_SHIFT	(mmu_pid_bits + 4)
>  #define PRTB_ENTRIES	(1ul << mmu_pid_bits)
>  
> -/*
> - * Power9 currently only support 64K partition table size.
> - */
> -#define PATB_SIZE_SHIFT	16
> +#define PATB_SIZE_SHIFT	(mmu_lpid_bits + 4)
> +#define PATB_ENTRIES	(1ul << mmu_lpid_bits)
>  
>  typedef unsigned long mm_context_id_t;
>  struct spinlock;
> diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
> index 9e16c7b1a6c5..13d1fbddecb9 100644
> --- a/arch/powerpc/mm/book3s64/pgtable.c
> +++ b/arch/powerpc/mm/book3s64/pgtable.c
> @@ -207,17 +207,12 @@ void __init mmu_partition_table_init(void)
>  	unsigned long patb_size = 1UL << PATB_SIZE_SHIFT;
>  	unsigned long ptcr;
>  
> -	BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 36), "Partition table size too large.");
>  	/* Initialize the Partition Table with no entries */
>  	partition_tb = memblock_alloc(patb_size, patb_size);
>  	if (!partition_tb)
>  		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
>  		      __func__, patb_size, patb_size);
>  
> -	/*
> -	 * update partition table control register,
> -	 * 64 K size.
> -	 */
>  	ptcr = __pa(partition_tb) | (PATB_SIZE_SHIFT - 12);
>  	set_ptcr_when_no_uv(ptcr);
>  	powernv_set_nmmu_ptcr(ptcr);
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index ae20add7954a..1c855434f8dc 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -33,7 +33,6 @@
>  
>  #include <trace/events/thp.h>
>  
> -unsigned int mmu_pid_bits;
>  unsigned int mmu_base_pid;
>  unsigned long radix_mem_block_size __ro_after_init;
>  
> @@ -357,18 +356,13 @@ static void __init radix_init_pgtable(void)
>  						-1, PAGE_KERNEL));
>  	}
>  
> -	/* Find out how many PID bits are supported */
>  	if (!cpu_has_feature(CPU_FTR_HVMODE) &&
>  			cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG)) {
>  		/*
>  		 * Older versions of KVM on these machines perfer if the
>  		 * guest only uses the low 19 PID bits.
>  		 */
> -		if (!mmu_pid_bits)
> -			mmu_pid_bits = 19;
> -	} else {
> -		if (!mmu_pid_bits)
> -			mmu_pid_bits = 20;
> +		mmu_pid_bits = 19;
>  	}
>  	mmu_base_pid = 1;
>  
> @@ -449,11 +443,6 @@ static int __init radix_dt_scan_page_sizes(unsigned long node,
>  	if (type == NULL || strcmp(type, "cpu") != 0)
>  		return 0;
>  
> -	/* Find MMU PID size */
> -	prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
> -	if (prop && size == 4)
> -		mmu_pid_bits = be32_to_cpup(prop);
> -
>  	/* Grab page size encodings */
>  	prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
>  	if (!prop)
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index 386be136026e..04f45fcb1222 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -370,6 +370,9 @@ void register_page_bootmem_memmap(unsigned long section_nr,
>  #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>  
>  #ifdef CONFIG_PPC_BOOK3S_64
> +unsigned int mmu_lpid_bits;
> +unsigned int mmu_pid_bits;
> +
>  static bool disable_radix = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT);
>  
>  static int __init parse_disable_radix(char *p)
> @@ -437,19 +440,61 @@ static void __init early_check_vec5(void)
>  	}
>  }
>  
> +static int __init dt_scan_mmu_pid_width(unsigned long node,
> +					   const char *uname, int depth,
> +					   void *data)
> +{
> +	int size = 0;
> +	const __be32 *prop;
> +	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
> +
> +	/* We are scanning "cpu" nodes only */
> +	if (type == NULL || strcmp(type, "cpu") != 0)
> +		return 0;
> +
> +	/* Find MMU LPID, PID register size */
> +	prop = of_get_flat_dt_prop(node, "ibm,mmu-lpid-bits", &size);
> +	if (prop && size == 4)
> +		mmu_lpid_bits = be32_to_cpup(prop);
> +
> +	prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
> +	if (prop && size == 4)
> +		mmu_pid_bits = be32_to_cpup(prop);
> +
> +	if (!mmu_pid_bits && !mmu_lpid_bits)
> +		return 0;
> +
> +	return 1;
> +}
> +
>  void __init mmu_early_init_devtree(void)
>  {
> +	int rc;
> +	bool hvmode = !!(mfmsr() & MSR_HV);
> +
>  	/* Disable radix mode based on kernel command line. */
>  	if (disable_radix)
>  		cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
>  
> +	rc = of_scan_flat_dt(dt_scan_mmu_pid_width, NULL);
> +	if (hvmode && !mmu_lpid_bits) {
> +		if (early_cpu_has_feature(CPU_FTR_ARCH_207S))
> +			mmu_lpid_bits = 12; /* POWER8-10 */
> +		else
> +			mmu_lpid_bits = 10; /* POWER7 */
> +	}
> +	if (!mmu_pid_bits) {
> +		if (early_cpu_has_feature(CPU_FTR_ARCH_300))
> +			mmu_pid_bits = 20; /* POWER9-10 */
> +	}
> +
>  	/*
>  	 * Check /chosen/ibm,architecture-vec-5 if running as a guest.
>  	 * When running bare-metal, we can use radix if we like
>  	 * even though the ibm,architecture-vec-5 property created by
>  	 * skiboot doesn't have the necessary bits set.
>  	 */
> -	if (!(mfmsr() & MSR_HV))
> +	if (!hvmode)
>  		early_check_vec5();
>  
>  	if (early_radix_enabled()) {

Re: [PATCH v2] powerpc/64s: Get LPID bit width from device tree

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 1977 bytes --]

Hi Nicholas,

I love your patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on v5.15 next-20211111]
[cannot apply to scottwood/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64s-Get-LPID-bit-width-from-device-tree/20211110-160038
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-buildonly-randconfig-r001-20211111 (attached as .config)
compiler: powerpc64le-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/b8fe7181506bf3011295456a9ee471ddf49d694d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nicholas-Piggin/powerpc-64s-Get-LPID-bit-width-from-device-tree/20211110-160038
        git checkout b8fe7181506bf3011295456a9ee471ddf49d694d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   arch/powerpc/mm/init_64.c: In function 'mmu_early_init_devtree':
>> arch/powerpc/mm/init_64.c:472:13: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
     472 |         int rc;
         |             ^~


vim +/rc +472 arch/powerpc/mm/init_64.c

   469	
   470	void __init mmu_early_init_devtree(void)
   471	{
 > 472		int rc;

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
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Re: [PATCH v2] powerpc/64s: Get LPID bit width from device tree

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 1975 bytes --]

Hi Nicholas,

I love your patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on v5.16-rc1 next-20211115]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64s-Get-LPID-bit-width-from-device-tree/20211110-160038
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-randconfig-c024-20211115 (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/b8fe7181506bf3011295456a9ee471ddf49d694d
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nicholas-Piggin/powerpc-64s-Get-LPID-bit-width-from-device-tree/20211110-160038
        git checkout b8fe7181506bf3011295456a9ee471ddf49d694d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   arch/powerpc/mm/init_64.c: In function 'mmu_early_init_devtree':
>> arch/powerpc/mm/init_64.c:472:13: error: variable 'rc' set but not used [-Werror=unused-but-set-variable]
     472 |         int rc;
         |             ^~
   cc1: all warnings being treated as errors


vim +/rc +472 arch/powerpc/mm/init_64.c

   469	
   470	void __init mmu_early_init_devtree(void)
   471	{
 > 472		int rc;

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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