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ACPI: CPPC: Use access_width over bit_width for system memory accesses
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commit 2f4a4d6 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@gregkh
Jarred White authored and gregkh committed May 2, 2024
1 parent 03170e6 commit 1b890ae
Showing 1 changed file with 26 additions and 5 deletions.
31 changes: 26 additions & 5 deletions drivers/acpi/cppc_acpi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -163,6 +163,13 @@ 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)
{
Expand Down Expand Up @@ -777,14 +784,16 @@ 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");
if (!cpc_supported_by_cpu())
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;
Expand Down Expand Up @@ -980,6 +989,7 @@ 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;

Expand All @@ -991,7 +1001,7 @@ 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;

Expand All @@ -1015,7 +1025,9 @@ 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;
Expand All @@ -1034,18 +1046,22 @@ 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,
Expand All @@ -1067,7 +1083,12 @@ 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;
Expand Down

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