ACPI: CPPC: Use access_width over bit_width for system memory accesses

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>

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index d155a86a861483e43d0952cc16cbf9ff8f9ef4c0..b954ce3638a9c88cd19647722f865db268700663 100644 (file)
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -166,6 +166,13 @@ 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)
 {
@@ -780,6 +787,7 @@ 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;
 
                                        if (!osc_cpc_flexible_adr_space_confirmed) {
                                                pr_debug("Flexible address space capability not supported\n");
@@ -787,7 +795,8 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
                                                        goto out_free;
                                        }
 
-                                       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;
@@ -983,6 +992,7 @@ int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
 static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
 {
        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;
 
@@ -994,7 +1004,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
        *val = 0;
 
        if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
-               u32 width = 8 << (reg->access_width - 1);
+               u32 width = GET_BIT_WIDTH(reg);
                u32 val_u32;
                acpi_status status;
 
@@ -1018,7 +1028,9 @@ 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;
@@ -1037,18 +1049,22 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
                return -EFAULT;
        }
 
+       if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+               *val = MASK_VAL(reg, *val);
+
        return 0;
 }
 
 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;
 
        if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
-               u32 width = 8 << (reg->access_width - 1);
+               u32 width = GET_BIT_WIDTH(reg);
                acpi_status status;
 
                status = acpi_os_write_port((acpi_io_address)reg->address,
@@ -1070,7 +1086,12 @@ 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;