diff options
author | Lv Zheng <lv.zheng@intel.com> | 2014-05-20 15:39:41 +0800 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-05-27 18:13:08 +0200 |
commit | a238317ce8185519ed083e81e84260907fbbcf7f (patch) | |
tree | f5b228ac40941946db2e7427b1085a90c78c85b5 /drivers/char/tpm/tpm_acpi.c | |
parent | 92985ef1db428cc6129a1d375a68c277aa05820b (diff) |
ACPI: Clean up acpi_os_map/unmap_memory() to eliminate __iomem.
ACPICA doesn't include protections around address space checking, Linux
build tests always complain increased sparse warnings around ACPICA
internal acpi_os_map/unmap_memory() invocations. This patch tries to fix
this issue permanently.
There are 2 choices left for us to solve this issue:
1. Add __iomem address space awareness into ACPICA.
2. Remove sparse checker of __iomem from ACPICA source code.
This patch chooses solution 2, because:
1. Most of the acpi_os_map/unmap_memory() invocations are used for ACPICA.
table mappings, which in fact are not IO addresses.
2. The only IO addresses usage is for "system memory space" mapping code in:
drivers/acpi/acpica/exregion.c
drivers/acpi/acpica/evrgnini.c
drivers/acpi/acpica/exregion.c
The mapped address is accessed in the handler of "system memory space"
- acpi_ex_system_memory_space_handler(). This function in fact can be
changed to invoke acpi_os_read/write_memory() so that __iomem can
always be type-casted in the OSL layer.
According to the above investigation, we drew the following conclusion:
It is not a good idea to introduce __iomem address space awareness into
ACPICA mostly in order to protect non-IO addresses.
We can simply remove __iomem for acpi_os_map/unmap_memory() to remove
__iomem checker for ACPICA code. Then we need to enforce external usages
to invoke other APIs that are aware of __iomem address space.
The external usages are:
drivers/acpi/apei/einj.c
drivers/acpi/acpi_extlog.c
drivers/char/tpm/tpm_acpi.c
drivers/acpi/nvs.c
This patch thus performs cleanups in this way:
1. Add acpi_os_map/unmap_iomem() to be invoked by non-ACPICA code.
2. Remove __iomem from acpi_os_map/unmap_memory().
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/char/tpm/tpm_acpi.c')
-rw-r--r-- | drivers/char/tpm/tpm_acpi.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c index b9a57fa4b710..565a9478cb94 100644 --- a/drivers/char/tpm/tpm_acpi.c +++ b/drivers/char/tpm/tpm_acpi.c @@ -95,7 +95,7 @@ int read_log(struct tpm_bios_log *log) log->bios_event_log_end = log->bios_event_log + len; - virt = acpi_os_map_memory(start, len); + virt = acpi_os_map_iomem(start, len); if (!virt) { kfree(log->bios_event_log); printk("%s: ERROR - Unable to map memory\n", __func__); @@ -104,6 +104,6 @@ int read_log(struct tpm_bios_log *log) memcpy_fromio(log->bios_event_log, virt, len); - acpi_os_unmap_memory(virt, len); + acpi_os_unmap_iomem(virt, len); return 0; } |