Current dependencies between amdkfd and radeon/amdgpu force the loading of amdkfd _before_ radeon and/or amdgpu are loaded. When all these kernel drivers are built as modules, this ordering is enforced by the kernel built-in mechanism of loading dependent modules.

However, there is no such mechanism in case where all these drivers are compiled inside the kernel image (not as modules). The current way to enforce loading of amdkfd before radeon/amdgpu, is to put amdkfd before radeon/amdgpu in the drm Makefile, but that method is way too fragile.

In addition, there is no kernel mechanism to check whether a kernel driver that is built inside the kernel image, has already been loaded.

To solve this, this patch adds to kfd_module.c a new static variable, amdkfd_init_completed, that is set to 1 only when amdkfd's module initialization function has been completed (successfully).

kgd2kfd_init(), which is the initialization function of the kgd-->kfd interface, and which is the first function in amdkfd called by radeon/amdgpu, will return successfully only if amdkfd_init_completed is equal 1.

If amdkfd_init_completed is not equal to 1, kgd2kfd_init() will return -EPROBE_DEFER to signal radeon/amdgpu they need to defer their loading until amdkfd is loaded.

Signed-off-by: Oded Gabbay oded.gabbay@gmail.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 4 ++-- drivers/gpu/drm/amd/amdkfd/kfd_module.c | 15 ++++++++++++--- drivers/gpu/drm/amd/include/kgd_kfd_interface.h | 2 +- drivers/gpu/drm/radeon/radeon_kfd.c | 4 ++-- 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c index 84d68d6..44ba8be 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c @@ -70,7 +70,7 @@ bool amdgpu_amdkfd_load_interface(struct amdgpu_device *rdev) return false; }

- if (!kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd)) { + if (kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd)) { symbol_put(kgd2kfd_init); kfd2kgd = NULL; kgd2kfd = NULL; @@ -80,7 +80,7 @@ bool amdgpu_amdkfd_load_interface(struct amdgpu_device *rdev)

return true; #elif defined(CONFIG_HSA_AMD) - if (!kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd)) { + if (kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd)) { kfd2kgd = NULL; kgd2kfd = NULL; return false; diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_module.c b/drivers/gpu/drm/amd/amdkfd/kfd_module.c index ca8410e..850a562 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_module.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_module.c @@ -59,18 +59,23 @@ module_param(send_sigterm, int, 0444); MODULE_PARM_DESC(send_sigterm, "Send sigterm to HSA process on unhandled exception (0 = disable, 1 = enable)");

-bool kgd2kfd_init(unsigned interface_version, const struct kgd2kfd_calls **g2f) +static int amdkfd_init_completed; + +int kgd2kfd_init(unsigned interface_version, const struct kgd2kfd_calls **g2f) { + if (!amdkfd_init_completed) + return -EPROBE_DEFER; + /* * Only one interface version is supported, * no kfd/kgd version skew allowed. */ if (interface_version != KFD_INTERFACE_VERSION) - return false; + return -EINVAL;

*g2f = &kgd2kfd;

- return true; + return 0; } EXPORT_SYMBOL(kgd2kfd_init);

@@ -111,6 +116,8 @@ static int __init kfd_module_init(void)

kfd_process_create_wq();

+ amdkfd_init_completed = 1; + dev_info(kfd_device, "Initialized module\n");

return 0; @@ -125,6 +132,8 @@ err_pasid:

static void __exit kfd_module_exit(void) { + amdkfd_init_completed = 0; + kfd_process_destroy_wq(); kfd_topology_shutdown(); kfd_chardev_exit(); diff --git a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h index 888250b..a09d9f3 100644 --- a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h +++ b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h @@ -221,7 +221,7 @@ struct kgd2kfd_calls { int (*resume)(struct kfd_dev *kfd); };

-bool kgd2kfd_init(unsigned interface_version, +int kgd2kfd_init(unsigned interface_version, const struct kgd2kfd_calls **g2f);

#endif /* KGD_KFD_INTERFACE_H_INCLUDED */ diff --git a/drivers/gpu/drm/radeon/radeon_kfd.c b/drivers/gpu/drm/radeon/radeon_kfd.c index 9a4d69e..83c2704 100644 --- a/drivers/gpu/drm/radeon/radeon_kfd.c +++ b/drivers/gpu/drm/radeon/radeon_kfd.c @@ -142,7 +142,7 @@ bool radeon_kfd_init(void) if (kgd2kfd_init_p == NULL) return false;

- if (!kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd)) { + if (kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd)) { symbol_put(kgd2kfd_init); kgd2kfd = NULL;

@@ -151,7 +151,7 @@ bool radeon_kfd_init(void)

return true; #elif defined(CONFIG_HSA_AMD) - if (!kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd)) { + if (kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd)) { kgd2kfd = NULL;

return false;

amdgpu must load only after amdkfd's loading has been completed. If that is not enforced, then amdgpu's call into amdkfd's functions will cause a kernel BUG.

When amdgpu and amdkfd are built as kernel modules, that rule is enforced by the kernel's modules loading mechanism. When amdgpu and amdkfd are built inside the kernel image, that rule is enforced by ordering in the drm Makefile (amdkfd before amdgpu).

Instead of using drm Makefile ordering, we can now use deferred loading as amdkfd now returns -EPROBE_DEFER in kgd2kfd_init() when it is not yet loaded.

This patch defers amdgpu loading by propagating -EPROBE_DEFER to the kernel's drivers loading infrastructure. That will put amdgpu into the pending drivers list (see description in dd.c). Once amdkfd is loaded, a call to kgd2kfd_init() will return successfully and amdgpu will be able to load.

Signed-off-by: Oded Gabbay oded.gabbay@gmail.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 57 +++++++++++------------------- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 2 +- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 10 ++++-- 3 files changed, 30 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c index 44ba8be..32809f7 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c @@ -30,25 +30,38 @@ const struct kfd2kgd_calls *kfd2kgd; const struct kgd2kfd_calls *kgd2kfd; bool (*kgd2kfd_init_p)(unsigned, const struct kgd2kfd_calls**);

-bool amdgpu_amdkfd_init(void) +int amdgpu_amdkfd_init(void) { + int ret; + #if defined(CONFIG_HSA_AMD_MODULE) - bool (*kgd2kfd_init_p)(unsigned, const struct kgd2kfd_calls**); + int (*kgd2kfd_init_p)(unsigned, const struct kgd2kfd_calls**);

kgd2kfd_init_p = symbol_request(kgd2kfd_init);

if (kgd2kfd_init_p == NULL) - return false; + return -ENOENT; + + ret = kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd); + if (ret) { + symbol_put(kgd2kfd_init); + kgd2kfd = NULL; + } + +#elif defined(CONFIG_HSA_AMD) + ret = kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd); + if (ret) + kgd2kfd = NULL; + +#else + ret = -ENOENT; #endif - return true; + + return ret; }

bool amdgpu_amdkfd_load_interface(struct amdgpu_device *rdev) { -#if defined(CONFIG_HSA_AMD_MODULE) - bool (*kgd2kfd_init_p)(unsigned, const struct kgd2kfd_calls**); -#endif - switch (rdev->asic_type) { #ifdef CONFIG_DRM_AMDGPU_CIK case CHIP_KAVERI: @@ -62,35 +75,7 @@ bool amdgpu_amdkfd_load_interface(struct amdgpu_device *rdev) return false; }

-#if defined(CONFIG_HSA_AMD_MODULE) - kgd2kfd_init_p = symbol_request(kgd2kfd_init); - - if (kgd2kfd_init_p == NULL) { - kfd2kgd = NULL; - return false; - } - - if (kgd2kfd_init_p(KFD_INTERFACE_VERSION, &kgd2kfd)) { - symbol_put(kgd2kfd_init); - kfd2kgd = NULL; - kgd2kfd = NULL; - - return false; - } - return true; -#elif defined(CONFIG_HSA_AMD) - if (kgd2kfd_init(KFD_INTERFACE_VERSION, &kgd2kfd)) { - kfd2kgd = NULL; - kgd2kfd = NULL; - return false; - } - - return true; -#else - kfd2kgd = NULL; - return false; -#endif }

void amdgpu_amdkfd_fini(void) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h index a8be765..de530f68d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h @@ -36,7 +36,7 @@ struct kgd_mem { void *cpu_ptr; };

-bool amdgpu_amdkfd_init(void); +int amdgpu_amdkfd_init(void); void amdgpu_amdkfd_fini(void);

bool amdgpu_amdkfd_load_interface(struct amdgpu_device *rdev); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c index 9c1af89..178519a 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -322,6 +322,14 @@ static int amdgpu_pci_probe(struct pci_dev *pdev, return -ENODEV; }

+ /* + * Initialize amdkfd before starting radeon. If it was not loaded yet, + * defer radeon probing + */ + ret = amdgpu_amdkfd_init(); + if (ret == -EPROBE_DEFER) + return ret; + /* Get rid of things like offb */ ret = amdgpu_kick_out_firmware_fb(pdev); if (ret) @@ -564,8 +572,6 @@ static int __init amdgpu_init(void) driver->num_ioctls = amdgpu_max_kms_ioctl; amdgpu_register_atpx_handler();

- amdgpu_amdkfd_init(); - /* let modprobe override vga console setting */ return drm_pci_init(driver, pdriver); }