[PATCH RESEND 5.15.y 0/3] Use access_width for _CPC package when provided by the platform firmware

[PATCH RESEND 5.15.y 0/3] Use access_width for _CPC package when provided by the platform firmware

[Easwar Hariharan]

This series backports the original patch[1] and fixes to it[2][3], all marked for
stable, that fix a kernel panic when using the wrong access size when
platform firmware provides the access size to use for the _CPC ACPI
package.

This series was originally sent in response to an automated email
notifying authors, reviewers, and maintainer of a failure to apply patch
[3] to linux-5.15.y at [4].

[1] 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses")
[2] 92ee782ee ("ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro").
[3] f489c948028b ("ACPI: CPPC: Fix access width used for PCC registers")
[4] https://lore.kernel.org/all/2024042905-puppy-heritage-e422@gregkh/

Easwar Hariharan (1):
  Revert "Revert "ACPI: CPPC: Use access_width over bit_width for system
    memory accesses""

Jarred White (1):
  ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro

Vanshidhar Konda (1):
  ACPI: CPPC: Fix access width used for PCC registers

 drivers/acpi/cppc_acpi.c | 67 +++++++++++++++++++++++++++++++++-------
 1 file changed, 56 insertions(+), 11 deletions(-)


base-commit: 284087d4f7d57502b5a41b423b771f16cc6d157a
-- 
2.34.1

[PATCH RESEND 5.15.y 1/3] Revert "Revert "ACPI: CPPC: Use access_width over bit_width for system memory accesses""

[Easwar Hariharan]

This reverts commit b54c4632946ae42f2b39ed38abd909bbf78cbcc2 which was a
revert of a backport of commit 2f4a4d63a193be6fd530d180bb13c3592052904c
upstream to 5.15.y.

Cc: Jarred White <jarredwhite@linux.microsoft.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
 drivers/acpi/cppc_acpi.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 7cc9183c8dc8e..408b1fda5702d 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -161,6 +161,13 @@ show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 
+/* Check for valid access_width, otherwise, fallback to using bit_width */
+#define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width)
+
+/* Shift and apply the mask for CPC reads/writes */
+#define MASK_VAL(reg, val) ((val) >> ((reg)->bit_offset & 			\
+					GENMASK(((reg)->bit_width), 0)))
+
 static ssize_t show_feedback_ctrs(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
 {
@@ -762,8 +769,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 			} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 				if (gas_t->address) {
 					void __iomem *addr;
+					size_t access_width;
 
-					addr = ioremap(gas_t->address, gas_t->bit_width/8);
+					access_width = GET_BIT_WIDTH(gas_t) / 8;
+					addr = ioremap(gas_t->address, access_width);
 					if (!addr)
 						goto out_free;
 					cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
@@ -936,6 +945,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
 	int ret_val = 0;
 	void __iomem *vaddr = NULL;
+	int size;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 
@@ -955,7 +965,9 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 		return acpi_os_read_memory((acpi_physical_address)reg->address,
 				val, reg->bit_width);
 
-	switch (reg->bit_width) {
+	size = GET_BIT_WIDTH(reg);
+
+	switch (size) {
 	case 8:
 		*val = readb_relaxed(vaddr);
 		break;
@@ -974,12 +986,16 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 		ret_val = -EFAULT;
 	}
 
+	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		*val = MASK_VAL(reg, *val);
+
 	return ret_val;
 }
 
 static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 {
 	int ret_val = 0;
+	int size;
 	void __iomem *vaddr = NULL;
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
@@ -994,7 +1010,12 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 		return acpi_os_write_memory((acpi_physical_address)reg->address,
 				val, reg->bit_width);
 
-	switch (reg->bit_width) {
+	size = GET_BIT_WIDTH(reg);
+
+	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		val = MASK_VAL(reg, val);
+
+	switch (size) {
 	case 8:
 		writeb_relaxed(val, vaddr);
 		break;
-- 
2.34.1

[PATCH RESEND 5.15.y 2/3] ACPI: CPPC: Fix bit_offset shift in MASK_VAL() macro

[Easwar Hariharan]

From: Jarred White <jarredwhite@linux.microsoft.com>

commit 05d92ee782eeb7b939bdd0189e6efcab9195bf95 upstream

Commit 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for
system memory accesses") neglected to properly wrap the bit_offset shift
when it comes to applying the mask. This may cause incorrect values to be
read and may cause the cpufreq module not be loaded.

[   11.059751] cpu_capacity: CPU0 missing/invalid highest performance.
[   11.066005] cpu_capacity: partial information: fallback to 1024 for all CPUs

Also, corrected the bitmask generation in GENMASK (extra bit being added).

Fixes: 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses")
Signed-off-by: Jarred White <jarredwhite@linux.microsoft.com>
Cc: 5.15+ <stable@vger.kernel.org> # 5.15+
Reviewed-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
 drivers/acpi/cppc_acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 408b1fda5702d..6aa456cda0ed9 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -165,8 +165,8 @@ show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 #define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width)
 
 /* Shift and apply the mask for CPC reads/writes */
-#define MASK_VAL(reg, val) ((val) >> ((reg)->bit_offset & 			\
-					GENMASK(((reg)->bit_width), 0)))
+#define MASK_VAL(reg, val) (((val) >> (reg)->bit_offset) & 			\
+					GENMASK(((reg)->bit_width) - 1, 0))
 
 static ssize_t show_feedback_ctrs(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
-- 
2.34.1

[PATCH RESEND 5.15.y 3/3] ACPI: CPPC: Fix access width used for PCC registers

[Easwar Hariharan]

From: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>

commit f489c948028b69cea235d9c0de1cc10eeb26a172 upstream

commit 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system
memory accesses") modified cpc_read()/cpc_write() to use access_width to
read CPC registers.

However, for PCC registers the access width field in the ACPI register
macro specifies the PCC subspace ID.  For non-zero PCC subspace ID it is
incorrectly treated as access width. This causes errors when reading
from PCC registers in the CPPC driver.

For PCC registers, base the size of read/write on the bit width field.
The debug message in cpc_read()/cpc_write() is updated to print relevant
information for the address space type used to read the register.

Fixes: 2f4a4d63a193 ("ACPI: CPPC: Use access_width over bit_width for system memory accesses")
Signed-off-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com>
Tested-by: Jarred White <jarredwhite@linux.microsoft.com>
Reviewed-by: Jarred White <jarredwhite@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Cc: 5.15+ <stable@vger.kernel.org> # 5.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[ eahariha: Backport to v5.15 by dropping SystemIO bits as commit
  a2c8f92bea5f is not present ]
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
---
 drivers/acpi/cppc_acpi.c | 48 ++++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 6aa456cda0ed9..6dcce036adb9c 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -955,17 +955,24 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 	}
 
 	*val = 0;
-	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
+	size = GET_BIT_WIDTH(reg);
+
+	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) {
+		/*
+		 * For registers in PCC space, the register size is determined
+		 * by the bit width field; the access size is used to indicate
+		 * the PCC subspace id.
+		 */
+		size = reg->bit_width;
 		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
+	}
 	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 		vaddr = reg_res->sys_mem_vaddr;
 	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
 		return cpc_read_ffh(cpu, reg, val);
 	else
 		return acpi_os_read_memory((acpi_physical_address)reg->address,
-				val, reg->bit_width);
-
-	size = GET_BIT_WIDTH(reg);
+				val, size);
 
 	switch (size) {
 	case 8:
@@ -981,8 +988,13 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 		*val = readq_relaxed(vaddr);
 		break;
 	default:
-		pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
-			 reg->bit_width, pcc_ss_id);
+		if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+			pr_debug("Error: Cannot read %u bit width from system memory: 0x%llx\n",
+				size, reg->address);
+		} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
+			pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
+				size, pcc_ss_id);
+		}
 		ret_val = -EFAULT;
 	}
 
@@ -1000,17 +1012,24 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
 	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
 
-	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
+	size = GET_BIT_WIDTH(reg);
+
+	if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) {
+		/*
+		 * For registers in PCC space, the register size is determined
+		 * by the bit width field; the access size is used to indicate
+		 * the PCC subspace id.
+		 */
+		size = reg->bit_width;
 		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
+	}
 	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 		vaddr = reg_res->sys_mem_vaddr;
 	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
 		return cpc_write_ffh(cpu, reg, val);
 	else
 		return acpi_os_write_memory((acpi_physical_address)reg->address,
-				val, reg->bit_width);
-
-	size = GET_BIT_WIDTH(reg);
+				val, size);
 
 	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
 		val = MASK_VAL(reg, val);
@@ -1029,8 +1048,13 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
 		writeq_relaxed(val, vaddr);
 		break;
 	default:
-		pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
-			 reg->bit_width, pcc_ss_id);
+		if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+			pr_debug("Error: Cannot write %u bit width to system memory: 0x%llx\n",
+				size, reg->address);
+		} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
+			pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
+				size, pcc_ss_id);
+		}
 		ret_val = -EFAULT;
 		break;
 	}
-- 
2.34.1

Re: [PATCH RESEND 5.15.y 0/3] Use access_width for _CPC package when provided by the platform firmware

[Sasha Levin]

On Thu, May 09, 2024 at 07:41:23PM +0000, Easwar Hariharan wrote:
>This series backports the original patch[1] and fixes to it[2][3], all marked for
>stable, that fix a kernel panic when using the wrong access size when
>platform firmware provides the access size to use for the _CPC ACPI
>package.
>
>This series was originally sent in response to an automated email
>notifying authors, reviewers, and maintainer of a failure to apply patch
>[3] to linux-5.15.y at [4].

Queued up, thanks!

-- 
Thanks,
Sasha