From a238317ce8185519ed083e81e84260907fbbcf7f Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Tue, 20 May 2014 15:39:41 +0800 Subject: 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 Signed-off-by: Rafael J. Wysocki --- drivers/char/tpm/tpm_acpi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c index b9a57fa..565a947 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; } -- cgit v1.1