| Message ID | 20200203161827.768-1-tli@digitalocean.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/radeon: have the callers of set_memory_*() check the return value | expand |
Am 03.02.20 um 17:18 schrieb Tianlin Li: > Right now several architectures allow their set_memory_*() family of > functions to fail, Oh, that is a detail I previously didn't recognized. Which architectures are that? Cause the RS400/480, RS690 and RS740 which are affected by this are integrated in the south-bridge. > but callers may not be checking the return values. > If set_memory_*() returns with an error, call-site assumptions may be > infact wrong to assume that it would either succeed or not succeed at > all. Ideally, the failure of set_memory_*() should be passed up the > call stack, and callers should examine the failure and deal with it. > > Need to fix the callers and add the __must_check attribute. They also > may not provide any level of atomicity, in the sense that the memory > protections may be left incomplete on failure. This issue likely has a > few steps on effects architectures: > 1)Have all callers of set_memory_*() helpers check the return value. > 2)Add __must_check to all set_memory_*() helpers so that new uses do > not ignore the return value. > 3)Add atomicity to the calls so that the memory protections aren't left > in a partial state. > > This series is part of step 1. Make drm/radeon check the return value of > set_memory_*(). > > Signed-off-by: Tianlin Li <tli@digitalocean.com> Reviewed-by: Christian König <christian.koenig@amd.com> > --- > v2: > The hardware is too old to be tested on and the code cannot be simply > removed from the kernel, so this is the solution for the short term. > - Just print an error when something goes wrong > - Remove patch 2. > v1: > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flkml%2F20200107192555.20606-1-tli%40digitalocean.com%2F&data=02%7C01%7Cchristian.koenig%40amd.com%7Cba2176d2ca834214e6b108d7a8c4bb1d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637163435227030235&sdata=mDhUEi3vmxahjsdrZOr83OEIWNBHefO8lkXST%2FW32CE%3D&reserved=0 > --- > drivers/gpu/drm/radeon/radeon_gart.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c > index f178ba321715..a2cc864aa08d 100644 > --- a/drivers/gpu/drm/radeon/radeon_gart.c > +++ b/drivers/gpu/drm/radeon/radeon_gart.c > @@ -80,8 +80,9 @@ int radeon_gart_table_ram_alloc(struct radeon_device *rdev) > #ifdef CONFIG_X86 > if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || > rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { > - set_memory_uc((unsigned long)ptr, > - rdev->gart.table_size >> PAGE_SHIFT); > + if (set_memory_uc((unsigned long)ptr, > + rdev->gart.table_size >> PAGE_SHIFT)) > + DRM_ERROR("set_memory_uc failed.\n"); > } > #endif > rdev->gart.ptr = ptr; > @@ -106,8 +107,9 @@ void radeon_gart_table_ram_free(struct radeon_device *rdev) > #ifdef CONFIG_X86 > if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || > rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { > - set_memory_wb((unsigned long)rdev->gart.ptr, > - rdev->gart.table_size >> PAGE_SHIFT); > + if (set_memory_wb((unsigned long)rdev->gart.ptr, > + rdev->gart.table_size >> PAGE_SHIFT)) > + DRM_ERROR("set_memory_wb failed.\n"); > } > #endif > pci_free_consistent(rdev->pdev, rdev->gart.table_size,
> On Feb 3, 2020, at 11:16 AM, Christian König <christian.koenig@amd.com> wrote: > > Am 03.02.20 um 17:18 schrieb Tianlin Li: >> Right now several architectures allow their set_memory_*() family of >> functions to fail, > > Oh, that is a detail I previously didn't recognized. Which architectures are that? > > Cause the RS400/480, RS690 and RS740 which are affected by this are integrated in the south-bridge. At least x86 is. Some details: https://lore.kernel.org/netdev/20180628213459.28631-4-daniel@iogearbox.net/ <https://lore.kernel.org/netdev/20180628213459.28631-4-daniel@iogearbox.net/> >> but callers may not be checking the return values. >> If set_memory_*() returns with an error, call-site assumptions may be >> infact wrong to assume that it would either succeed or not succeed at >> all. Ideally, the failure of set_memory_*() should be passed up the >> call stack, and callers should examine the failure and deal with it. >> >> Need to fix the callers and add the __must_check attribute. They also >> may not provide any level of atomicity, in the sense that the memory >> protections may be left incomplete on failure. This issue likely has a >> few steps on effects architectures: >> 1)Have all callers of set_memory_*() helpers check the return value. >> 2)Add __must_check to all set_memory_*() helpers so that new uses do >> not ignore the return value. >> 3)Add atomicity to the calls so that the memory protections aren't left >> in a partial state. >> >> This series is part of step 1. Make drm/radeon check the return value of >> set_memory_*(). >> >> Signed-off-by: Tianlin Li <tli@digitalocean.com> > > Reviewed-by: Christian König <christian.koenig@amd.com <mailto:christian.koenig@amd.com>> > >> --- >> v2: >> The hardware is too old to be tested on and the code cannot be simply >> removed from the kernel, so this is the solution for the short term. >> - Just print an error when something goes wrong >> - Remove patch 2. >> v1: >> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flkml%2F20200107192555.20606-1-tli%40digitalocean.com%2F&data=02%7C01%7Cchristian.koenig%40amd.com%7Cba2176d2ca834214e6b108d7a8c4bb1d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637163435227030235&sdata=mDhUEi3vmxahjsdrZOr83OEIWNBHefO8lkXST%2FW32CE%3D&reserved=0 <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flkml%2F20200107192555.20606-1-tli%40digitalocean.com%2F&data=02%7C01%7Cchristian.koenig%40amd.com%7Cba2176d2ca834214e6b108d7a8c4bb1d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637163435227030235&sdata=mDhUEi3vmxahjsdrZOr83OEIWNBHefO8lkXST%2FW32CE%3D&reserved=0> >> --- >> drivers/gpu/drm/radeon/radeon_gart.c | 10 ++++++---- >> 1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c >> index f178ba321715..a2cc864aa08d 100644 >> --- a/drivers/gpu/drm/radeon/radeon_gart.c >> +++ b/drivers/gpu/drm/radeon/radeon_gart.c >> @@ -80,8 +80,9 @@ int radeon_gart_table_ram_alloc(struct radeon_device *rdev) >> #ifdef CONFIG_X86 >> if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || >> rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { >> - set_memory_uc((unsigned long)ptr, >> - rdev->gart.table_size >> PAGE_SHIFT); >> + if (set_memory_uc((unsigned long)ptr, >> + rdev->gart.table_size >> PAGE_SHIFT)) >> + DRM_ERROR("set_memory_uc failed.\n"); >> } >> #endif >> rdev->gart.ptr = ptr; >> @@ -106,8 +107,9 @@ void radeon_gart_table_ram_free(struct radeon_device *rdev) >> #ifdef CONFIG_X86 >> if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || >> rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { >> - set_memory_wb((unsigned long)rdev->gart.ptr, >> - rdev->gart.table_size >> PAGE_SHIFT); >> + if (set_memory_wb((unsigned long)rdev->gart.ptr, >> + rdev->gart.table_size >> PAGE_SHIFT)) >> + DRM_ERROR("set_memory_wb failed.\n"); >> } >> #endif >> pci_free_consistent(rdev->pdev, rdev->gart.table_size,
diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c index f178ba321715..a2cc864aa08d 100644 --- a/drivers/gpu/drm/radeon/radeon_gart.c +++ b/drivers/gpu/drm/radeon/radeon_gart.c @@ -80,8 +80,9 @@ int radeon_gart_table_ram_alloc(struct radeon_device *rdev) #ifdef CONFIG_X86 if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { - set_memory_uc((unsigned long)ptr, - rdev->gart.table_size >> PAGE_SHIFT); + if (set_memory_uc((unsigned long)ptr, + rdev->gart.table_size >> PAGE_SHIFT)) + DRM_ERROR("set_memory_uc failed.\n"); } #endif rdev->gart.ptr = ptr; @@ -106,8 +107,9 @@ void radeon_gart_table_ram_free(struct radeon_device *rdev) #ifdef CONFIG_X86 if (rdev->family == CHIP_RS400 || rdev->family == CHIP_RS480 || rdev->family == CHIP_RS690 || rdev->family == CHIP_RS740) { - set_memory_wb((unsigned long)rdev->gart.ptr, - rdev->gart.table_size >> PAGE_SHIFT); + if (set_memory_wb((unsigned long)rdev->gart.ptr, + rdev->gart.table_size >> PAGE_SHIFT)) + DRM_ERROR("set_memory_wb failed.\n"); } #endif pci_free_consistent(rdev->pdev, rdev->gart.table_size,
Right now several architectures allow their set_memory_*() family of functions to fail, but callers may not be checking the return values. If set_memory_*() returns with an error, call-site assumptions may be infact wrong to assume that it would either succeed or not succeed at all. Ideally, the failure of set_memory_*() should be passed up the call stack, and callers should examine the failure and deal with it. Need to fix the callers and add the __must_check attribute. They also may not provide any level of atomicity, in the sense that the memory protections may be left incomplete on failure. This issue likely has a few steps on effects architectures: 1)Have all callers of set_memory_*() helpers check the return value. 2)Add __must_check to all set_memory_*() helpers so that new uses do not ignore the return value. 3)Add atomicity to the calls so that the memory protections aren't left in a partial state. This series is part of step 1. Make drm/radeon check the return value of set_memory_*(). Signed-off-by: Tianlin Li <tli@digitalocean.com> --- v2: The hardware is too old to be tested on and the code cannot be simply removed from the kernel, so this is the solution for the short term. - Just print an error when something goes wrong - Remove patch 2. v1: https://lore.kernel.org/lkml/20200107192555.20606-1-tli@digitalocean.com/ --- drivers/gpu/drm/radeon/radeon_gart.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)