Hi Greg, Sasha,

commit 2f4a4d63a193be6fd530d180bb13c3592052904c upstream is marked for 5.15+ with CC: stable@vger.kernel.org, but the application will fail with a merge conflict due to missing intermediate feature patches. When you apply the patch to 5.15, could you take the backport below instead?

Thanks, Easwar PS: It will apply cleanly to the other stable branches.

----8x--------------------------

From ab7a492bcec34a3ad4ae4e2a6ad0e7e1c4fc783a Mon Sep 17 00:00:00 2001 From: Jarred White jarredwhite@linux.microsoft.com Date: Fri, 1 Mar 2024 11:25:59 -0800 Subject: [PATCH 1/1] ACPI: CPPC: Use access_width over bit_width for system memory accesses

commit 2f4a4d63a193be6fd530d180bb13c3592052904c upstream

To align with ACPI 6.3+, since bit_width can be any 8-bit value, it cannot be depended on to be always on a clean 8b boundary. This was uncovered on the Cobalt 100 platform.

SError Interrupt on CPU26, code 0xbe000011 -- SError CPU: 26 PID: 1510 Comm: systemd-udevd Not tainted 5.15.2.1-13 #1 Hardware name: MICROSOFT CORPORATION, BIOS MICROSOFT CORPORATION pstate: 62400009 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : cppc_get_perf_caps+0xec/0x410 lr : cppc_get_perf_caps+0xe8/0x410 sp : ffff8000155ab730 x29: ffff8000155ab730 x28: ffff0080139d0038 x27: ffff0080139d0078 x26: 0000000000000000 x25: ffff0080139d0058 x24: 00000000ffffffff x23: ffff0080139d0298 x22: ffff0080139d0278 x21: 0000000000000000 x20: ffff00802b251910 x19: ffff0080139d0000 x18: ffffffffffffffff x17: 0000000000000000 x16: ffffdc7e111bad04 x15: ffff00802b251008 x14: ffffffffffffffff x13: ffff013f1fd63300 x12: 0000000000000006 x11: ffffdc7e128f4420 x10: 0000000000000000 x9 : ffffdc7e111badec x8 : ffff00802b251980 x7 : 0000000000000000 x6 : ffff0080139d0028 x5 : 0000000000000000 x4 : ffff0080139d0018 x3 : 00000000ffffffff x2 : 0000000000000008 x1 : ffff8000155ab7a0 x0 : 0000000000000000 Kernel panic - not syncing: Asynchronous SError Interrupt CPU: 26 PID: 1510 Comm: systemd-udevd Not tainted 5.15.2.1-13 #1 Hardware name: MICROSOFT CORPORATION, BIOS MICROSOFT CORPORATION Call trace: dump_backtrace+0x0/0x1e0 show_stack+0x24/0x30 dump_stack_lvl+0x8c/0xb8 dump_stack+0x18/0x34 panic+0x16c/0x384 add_taint+0x0/0xc0 arm64_serror_panic+0x7c/0x90 arm64_is_fatal_ras_serror+0x34/0xa4 do_serror+0x50/0x6c el1h_64_error_handler+0x40/0x74 el1h_64_error+0x7c/0x80 cppc_get_perf_caps+0xec/0x410 cppc_cpufreq_cpu_init+0x74/0x400 [cppc_cpufreq] cpufreq_online+0x2dc/0xa30 cpufreq_add_dev+0xc0/0xd4 subsys_interface_register+0x134/0x14c cpufreq_register_driver+0x1b0/0x354 cppc_cpufreq_init+0x1a8/0x1000 [cppc_cpufreq] do_one_initcall+0x50/0x250 do_init_module+0x60/0x27c load_module+0x2300/0x2570 __do_sys_finit_module+0xa8/0x114 __arm64_sys_finit_module+0x2c/0x3c invoke_syscall+0x78/0x100 el0_svc_common.constprop.0+0x180/0x1a0 do_el0_svc+0x84/0xa0 el0_svc+0x2c/0xc0 el0t_64_sync_handler+0xa4/0x12c el0t_64_sync+0x1a4/0x1a8

Instead, use access_width to determine the size and use the offset and width to shift and mask the bits to read/write out. Make sure to add a check for system memory since pcc redefines the access_width to subspace id.

If access_width is not set, then fall back to using bit_width.

Signed-off-by: Jarred White jarredwhite@linux.microsoft.com Reviewed-by: Easwar Hariharan eahariha@linux.microsoft.com Cc: 5.15+ stable@vger.kernel.org # 5.15+ [ rjw: Subject and changelog edits, comment adjustments ] 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 | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 7cc9183c8dc8..408b1fda5702 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;