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[91.14.161.181]) by smtp.gmail.com with ESMTPSA id m5sm5166653wmi.1.2021.08.25.05.07.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 25 Aug 2021 05:07:47 -0700 (PDT) Subject: Re: [PATCH] drm/amd/amdgpu: New debugfs interface for MMIO registers (v2) To: Tom St Denis , "Das, Nirmoy" Cc: Tom St Denis , amd-gfx mailing list References: <20210824133642.109072-1-tom.stdenis@amd.com> <84ddce49-012b-2fae-d14d-eeebf7e6c09a@gmail.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: Date: Wed, 25 Aug 2021 14:07:45 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------900395F795CA7743CE25542F" Content-Language: en-US X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" This is a multi-part message in MIME format. --------------900395F795CA7743CE25542F Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sounds good enough to me. Just be extra careful should you extend this with u64 or anything which depends on 32 vs 64 bit architecture (like pointers and long) at some point. Christian. Am 25.08.21 um 13:31 schrieb Tom St Denis: > 1 hole with u8, 0 holes with u32.  Is good? > > On Wed, Aug 25, 2021 at 7:16 AM Das, Nirmoy > wrote: > > > On 8/25/2021 1:09 PM, Christian König wrote: >> I suggest to give this command here at least a try (remembered >> the name after a moment): >> >> pahole drivers/gpu/drm/amd/amdgpu/amdgpu.o -C >> amdgpu_debugfs_regs2_iocdata >> >> It has a rather nifty output with padding holes, byte addresses, >> cache lines etc for your structure. >> >> Christian. >> >> Am 25.08.21 um 13:04 schrieb Tom St Denis: >>> I tested it by forcing bit patterns into the ioctl data and >>> printing it out in the kernel log. I'm not siloed into it one >>> way or the other.  I'll just change it to u32. >>> >>> On Wed, Aug 25, 2021 at 7:03 AM Christian König >>> >> > wrote: >>> >>> Using u8 is ok as well, just make sure that you don't have >>> any hidden padding. >>> >>> Nirmoy had a tool to double check for paddings which I once >>> more forgot the name of. >>> > > Yes, pahole. pkg name: dwarves > > > Nirmoy > > >>> >>> Christian. >>> >>> Am 25.08.21 um 12:40 schrieb Tom St Denis: >>>> The struct works as is but I'll change them to u32.  The >>>> offset is an artefact of the fact this was an IOCTL >>>> originally.  I'm working both ends in parallel trying to >>>> make the changes at the same time because I'm only >>>> submitting the kernel patch if I've tested it in userspace. >>>> >>>> I'll send a v4 in a bit this morning.... >>>> >>>> Tom >>>> >>>> On Wed, Aug 25, 2021 at 2:35 AM Christian König >>>> >>> > wrote: >>>> >>>> >>>> >>>> Am 24.08.21 um 15:36 schrieb Tom St Denis: >>>> > This new debugfs interface uses an IOCTL interface in >>>> order to pass >>>> > along state information like SRBM and GRBM bank >>>> switching.  This >>>> > new interface also allows a full 32-bit MMIO address >>>> range which >>>> > the previous didn't.  With this new design we have >>>> room to grow >>>> > the flexibility of the file as need be. >>>> > >>>> > (v2): Move read/write to .read/.write, fix style, add >>>> comment >>>> >        for IOCTL data structure >>>> > >>>> > Signed-off-by: Tom St Denis >>> > >>>> > --- >>>> >  drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 162 >>>> ++++++++++++++++++++ >>>> >  drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h |  32 ++++ >>>> >   2 files changed, 194 insertions(+) >>>> > >>>> > diff --git >>>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c >>>> > index 277128846dd1..8e8f5743c8f5 100644 >>>> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c >>>> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c >>>> > @@ -279,6 +279,156 @@ static ssize_t >>>> amdgpu_debugfs_regs_write(struct file *f, const char >>>> __user *buf, >>>> >       return amdgpu_debugfs_process_reg_op(false, f, >>>> (char __user *)buf, size, pos); >>>> >   } >>>> > >>>> > +static int amdgpu_debugfs_regs2_open(struct inode >>>> *inode, struct file *file) >>>> > +{ >>>> > +     struct amdgpu_debugfs_regs2_data *rd; >>>> > + >>>> > +     rd = kzalloc(sizeof *rd, GFP_KERNEL); >>>> > +     if (!rd) >>>> > +             return -ENOMEM; >>>> > +     rd->adev = file_inode(file)->i_private; >>>> > +     file->private_data = rd; >>>> > + >>>> > +     return 0; >>>> > +} >>>> > + >>>> > +static int amdgpu_debugfs_regs2_release(struct inode >>>> *inode, struct file *file) >>>> > +{ >>>> > +     kfree(file->private_data); >>>> > +     return 0; >>>> > +} >>>> > + >>>> > +static ssize_t amdgpu_debugfs_regs2_op(struct file >>>> *f, char __user *buf, size_t size, int write_en) >>>> > +{ >>>> > +     struct amdgpu_debugfs_regs2_data *rd = >>>> f->private_data; >>>> > +     struct amdgpu_device *adev = rd->adev; >>>> > +     ssize_t result = 0; >>>> > +     int r; >>>> > +     uint32_t value; >>>> > + >>>> > +     if (size & 0x3 || rd->state.offset & 0x3) >>>> > +             return -EINVAL; >>>> > + >>>> > +     if (rd->state.id.use_grbm) { >>>> > +             if (rd->state.id.grbm.se >>>> >>>> == 0x3FF) >>>> > +                     rd->state.id.grbm.se >>>> >>>> = 0xFFFFFFFF; >>>> > +             if (rd->state.id.grbm.sh >>>> >>>> == 0x3FF) >>>> > +                     rd->state.id.grbm.sh >>>> >>>> = 0xFFFFFFFF; >>>> > +             if (rd->state.id.grbm.instance == 0x3FF) >>>> > +  rd->state.id.grbm.instance = 0xFFFFFFFF; >>>> > +     } >>>> > + >>>> > +     r = pm_runtime_get_sync(adev_to_drm(adev)->dev); >>>> > +     if (r < 0) { >>>> > +  pm_runtime_put_autosuspend(adev_to_drm(adev)->dev); >>>> > +             return r; >>>> > +     } >>>> > + >>>> > +     r = amdgpu_virt_enable_access_debugfs(adev); >>>> > +     if (r < 0) { >>>> > +  pm_runtime_put_autosuspend(adev_to_drm(adev)->dev); >>>> > +             return r; >>>> > +     } >>>> > + >>>> > +     if (rd->state.id.use_grbm) { >>>> > +             if ((rd->state.id.grbm.sh >>>> >>>> != 0xFFFFFFFF && rd->state.id.grbm.sh >>>> >>>> >= adev->gfx.config.max_sh_per_se) || >>>> > +                 (rd->state.id.grbm.se >>>> >>>> != 0xFFFFFFFF && rd->state.id.grbm.se >>>> >>>> >= adev->gfx.config.max_shader_engines)) { >>>> > +  pm_runtime_mark_last_busy(adev_to_drm(adev)->dev); >>>> > +  pm_runtime_put_autosuspend(adev_to_drm(adev)->dev); >>>> > +  amdgpu_virt_disable_access_debugfs(adev); >>>> > +                     return -EINVAL; >>>> > +             } >>>> > +  mutex_lock(&adev->grbm_idx_mutex); >>>> > +  amdgpu_gfx_select_se_sh(adev, rd->state.id.grbm.se >>>> , >>>> > +                        rd->state.id.grbm.sh >>>> , >>>> > +  rd->state.id.grbm.instance); >>>> > +     } >>>> > + >>>> > +     if (rd->state.id.use_srbm) { >>>> > +  mutex_lock(&adev->srbm_mutex); >>>> > +  amdgpu_gfx_select_me_pipe_q(adev, >>>> rd->state.id.srbm.me >>>> , >>>> rd->state.id.srbm.pipe, >>>> > +  rd->state.id.srbm.queue, rd->state.id.srbm.vmid); >>>> > +     } >>>> > + >>>> > +     if (rd->state.id.pg_lock) >>>> > +  mutex_lock(&adev->pm.mutex); >>>> > + >>>> > +     while (size) { >>>> > +             if (!write_en) { >>>> > +                     value = RREG32(rd->state.offset >>>> >> 2); >>>> > +                     r = put_user(value, (uint32_t >>>> *)buf); >>>> > +             } else { >>>> > +                     r = get_user(value, (uint32_t >>>> *)buf); >>>> > +                     if (!r) >>>> > +  amdgpu_mm_wreg_mmio_rlc(adev, rd->state.offset >> >>>> 2, value); >>>> > +             } >>>> > +             if (r) { >>>> > +                     result = r; >>>> > +                     goto end; >>>> > +             } >>>> > +             rd->state.offset += 4; >>>> > +             size -= 4; >>>> > +             result += 4; >>>> > +             buf += 4; >>>> > +     } >>>> > +end: >>>> > +     if (rd->state.id.use_grbm) { >>>> > +  amdgpu_gfx_select_se_sh(adev, 0xffffffff, >>>> 0xffffffff, 0xffffffff); >>>> > +  mutex_unlock(&adev->grbm_idx_mutex); >>>> > +     } >>>> > + >>>> > +     if (rd->state.id.use_srbm) { >>>> > +  amdgpu_gfx_select_me_pipe_q(adev, 0, 0, 0, 0); >>>> > +  mutex_unlock(&adev->srbm_mutex); >>>> > +     } >>>> > + >>>> > +     if (rd->state.id.pg_lock) >>>> > +  mutex_unlock(&adev->pm.mutex); >>>> > + >>>> > +     // in umr (the likely user of this) flags are >>>> set per file operation >>>> > +     // which means they're never "unset" >>>> explicitly.  To avoid breaking >>>> > +     // this convention we unset the flags after >>>> each operation >>>> > +     // flags are for a single call (need to be set >>>> for every read/write) >>>> > +     rd->state.id.use_grbm = 0; >>>> > +     rd->state.id.use_srbm = 0; >>>> > +     rd->state.id.pg_lock  = 0; >>>> > + >>>> > +  pm_runtime_mark_last_busy(adev_to_drm(adev)->dev); >>>> > +  pm_runtime_put_autosuspend(adev_to_drm(adev)->dev); >>>> > + >>>> > +  amdgpu_virt_disable_access_debugfs(adev); >>>> > +     return result; >>>> > +} >>>> > + >>>> > +static long amdgpu_debugfs_regs2_ioctl(struct file >>>> *f, unsigned int cmd, unsigned long data) >>>> > +{ >>>> > +     struct amdgpu_debugfs_regs2_data *rd = >>>> f->private_data; >>>> > + >>>> > +     switch (cmd) { >>>> > +     case AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE: >>>> > +             if (copy_from_user(&rd->state.id >>>> , >>>> (struct amdgpu_debugfs_regs2_iocdata *)data, sizeof >>>> rd->state.id >>>> )) >>>> > +                     return -EINVAL; >>>> > +             break; >>>> > +     default: >>>> > +             return -EINVAL; >>>> > +     } >>>> > +     return 0; >>>> > +} >>>> > + >>>> > +static ssize_t amdgpu_debugfs_regs2_read(struct file >>>> *f, char __user *buf, size_t size, loff_t *pos) >>>> > +{ >>>> > +     struct amdgpu_debugfs_regs2_data *rd = >>>> f->private_data; >>>> > +     rd->state.offset = *pos; >>>> > +     return amdgpu_debugfs_regs2_op(f, buf, size, 0); >>>> > +} >>>> > + >>>> > +static ssize_t amdgpu_debugfs_regs2_write(struct >>>> file *f, const char __user *buf, size_t size, loff_t *pos) >>>> > +{ >>>> > +     struct amdgpu_debugfs_regs2_data *rd = >>>> f->private_data; >>>> > +     rd->state.offset = *pos; >>>> > +     return amdgpu_debugfs_regs2_op(f, (char __user >>>> *)buf, size, 1); >>>> > +} >>>> > + >>>> > >>>> >   /** >>>> >    * amdgpu_debugfs_regs_pcie_read - Read from a PCIE >>>> register >>>> > @@ -1091,6 +1241,16 @@ static ssize_t >>>> amdgpu_debugfs_gfxoff_read(struct file *f, char __user >>>> *buf, >>>> >       return result; >>>> >   } >>>> > >>>> > +static const struct file_operations >>>> amdgpu_debugfs_regs2_fops = { >>>> > +     .owner = THIS_MODULE, >>>> > +     .unlocked_ioctl = amdgpu_debugfs_regs2_ioctl, >>>> > +     .read = amdgpu_debugfs_regs2_read, >>>> > +     .write = amdgpu_debugfs_regs2_write, >>>> > +     .open = amdgpu_debugfs_regs2_open, >>>> > +     .release = amdgpu_debugfs_regs2_release, >>>> > +     .llseek = default_llseek >>>> > +}; >>>> > + >>>> >   static const struct file_operations >>>> amdgpu_debugfs_regs_fops = { >>>> >       .owner = THIS_MODULE, >>>> >       .read = amdgpu_debugfs_regs_read, >>>> > @@ -1148,6 +1308,7 @@ static const struct >>>> file_operations amdgpu_debugfs_gfxoff_fops = { >>>> > >>>> >   static const struct file_operations *debugfs_regs[] = { >>>> >       &amdgpu_debugfs_regs_fops, >>>> > +     &amdgpu_debugfs_regs2_fops, >>>> >  &amdgpu_debugfs_regs_didt_fops, >>>> >  &amdgpu_debugfs_regs_pcie_fops, >>>> >  &amdgpu_debugfs_regs_smc_fops, >>>> > @@ -1160,6 +1321,7 @@ static const struct >>>> file_operations *debugfs_regs[] = { >>>> > >>>> >   static const char *debugfs_regs_names[] = { >>>> >       "amdgpu_regs", >>>> > +     "amdgpu_regs2", >>>> >       "amdgpu_regs_didt", >>>> >       "amdgpu_regs_pcie", >>>> >       "amdgpu_regs_smc", >>>> > diff --git >>>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h >>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h >>>> > index 141a8474e24f..ec044df5d428 100644 >>>> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h >>>> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h >>>> > @@ -22,6 +22,8 @@ >>>> >    * OTHER DEALINGS IN THE SOFTWARE. >>>> >    * >>>> >    */ >>>> > +#include >>>> > +#include >>>> > >>>> >   /* >>>> >    * Debugfs >>>> > @@ -38,3 +40,33 @@ void >>>> amdgpu_debugfs_fence_init(struct amdgpu_device *adev); >>>> >   void amdgpu_debugfs_firmware_init(struct >>>> amdgpu_device *adev); >>>> >   void amdgpu_debugfs_gem_init(struct amdgpu_device >>>> *adev); >>>> >   int amdgpu_debugfs_wait_dump(struct amdgpu_device >>>> *adev); >>>> > + >>>> > +/* >>>> > + * MMIO debugfs IOCTL structure >>>> > + */ >>>> > +struct amdgpu_debugfs_regs2_iocdata { >>>> > +     __u8 use_srbm, use_grbm, pg_lock; >>>> >>>> You should consider using u32 here as well or add >>>> explicitly padding. >>>> >>>> > +     struct { >>>> > +             __u32 se, sh, instance; >>>> > +     } grbm; >>>> > +     struct { >>>> > +             __u32 me, pipe, queue, vmid; >>>> > +     } srbm; >>>> > +}; >>>> > + >>>> > +/* >>>> > + * MMIO debugfs state data (per file* handle) >>>> > + */ >>>> > +struct amdgpu_debugfs_regs2_data { >>>> > +     struct amdgpu_device *adev; >>>> > +     struct { >>>> > +             struct amdgpu_debugfs_regs2_iocdata id; >>>> > +             __u32 offset; >>>> >>>> What is the offset good for here? >>>> >>>> Regards, >>>> Christian. >>>> >>>> > +     } state; >>>> > +}; >>>> > + >>>> > +enum AMDGPU_DEBUGFS_REGS2_CMDS { >>>> > +  AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE=0, >>>> > +}; >>>> > + >>>> > +#define AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE >>>> _IOWR(0x20, AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE, struct >>>> amdgpu_debugfs_regs2_iocdata) >>>> >>> >> --------------900395F795CA7743CE25542F Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Sounds good enough to me. Just be extra careful should you extend this with u64 or anything which depends on 32 vs 64 bit architecture (like pointers and long) at some point.

Christian.

Am 25.08.21 um 13:31 schrieb Tom St Denis:
1 hole with u8, 0 holes with u32.  Is good?

On Wed, Aug 25, 2021 at 7:16 AM Das, Nirmoy <nirmoy.das@amd.com> wrote:


On 8/25/2021 1:09 PM, Christian König wrote:
I suggest to give this command here at least a try (remembered the name after a moment):

pahole drivers/gpu/drm/amd/amdgpu/amdgpu.o -C amdgpu_debugfs_regs2_iocdata

It has a rather nifty output with padding holes, byte addresses, cache lines etc for your structure.

Christian.

Am 25.08.21 um 13:04 schrieb Tom St Denis:
I tested it by forcing bit patterns into the ioctl data and printing it out in the kernel log.  I'm not siloed into it one way or the other.  I'll just change it to u32.

On Wed, Aug 25, 2021 at 7:03 AM Christian König <ckoenig.leichtzumerken@gmail.com> wrote:
Using u8 is ok as well, just make sure that you don't have any hidden padding.

Nirmoy had a tool to double check for paddings which I once more forgot the name of.


Yes, pahole. pkg name: dwarves


Nirmoy



Christian.

Am 25.08.21 um 12:40 schrieb Tom St Denis:
The struct works as is but I'll change them to u32.  The offset is an artefact of the fact this was an IOCTL originally.  I'm working both ends in parallel trying to make the changes at the same time because I'm only submitting the kernel patch if I've tested it in userspace.

I'll send a v4 in a bit this morning....

Tom

On Wed, Aug 25, 2021 at 2:35 AM Christian König <ckoenig.leichtzumerken@gmail.com> wrote:


Am 24.08.21 um 15:36 schrieb Tom St Denis:
> This new debugfs interface uses an IOCTL interface in order to pass
> along state information like SRBM and GRBM bank switching.  This
> new interface also allows a full 32-bit MMIO address range which
> the previous didn't.  With this new design we have room to grow
> the flexibility of the file as need be.
>
> (v2): Move read/write to .read/.write, fix style, add comment
>        for IOCTL data structure
>
> Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 162 ++++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h |  32 ++++
>   2 files changed, 194 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> index 277128846dd1..8e8f5743c8f5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> @@ -279,6 +279,156 @@ static ssize_t amdgpu_debugfs_regs_write(struct file *f, const char __user *buf,
>       return amdgpu_debugfs_process_reg_op(false, f, (char __user *)buf, size, pos);
>   }
>   
> +static int amdgpu_debugfs_regs2_open(struct inode *inode, struct file *file)
> +{
> +     struct amdgpu_debugfs_regs2_data *rd;
> +
> +     rd = kzalloc(sizeof *rd, GFP_KERNEL);
> +     if (!rd)
> +             return -ENOMEM;
> +     rd->adev = file_inode(file)->i_private;
> +     file->private_data = rd;
> +
> +     return 0;
> +}
> +
> +static int amdgpu_debugfs_regs2_release(struct inode *inode, struct file *file)
> +{
> +     kfree(file->private_data);
> +     return 0;
> +}
> +
> +static ssize_t amdgpu_debugfs_regs2_op(struct file *f, char __user *buf, size_t size, int write_en)
> +{
> +     struct amdgpu_debugfs_regs2_data *rd = f->private_data;
> +     struct amdgpu_device *adev = rd->adev;
> +     ssize_t result = 0;
> +     int r;
> +     uint32_t value;
> +
> +     if (size & 0x3 || rd->state.offset & 0x3)
> +             return -EINVAL;
> +
> +     if (rd->state.id.use_grbm) {
> +             if (rd->state.id.grbm.se == 0x3FF)
> +                     rd->state.id.grbm.se = 0xFFFFFFFF;
> +             if (rd->state.id.grbm.sh == 0x3FF)
> +                     rd->state.id.grbm.sh = 0xFFFFFFFF;
> +             if (rd->state.id.grbm.instance == 0x3FF)
> +                     rd->state.id.grbm.instance = 0xFFFFFFFF;
> +     }
> +
> +     r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
> +     if (r < 0) {
> +             pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
> +             return r;
> +     }
> +
> +     r = amdgpu_virt_enable_access_debugfs(adev);
> +     if (r < 0) {
> +             pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
> +             return r;
> +     }
> +
> +     if (rd->state.id.use_grbm) {
> +             if ((rd->state.id.grbm.sh != 0xFFFFFFFF && rd->state.id.grbm.sh >= adev->gfx.config.max_sh_per_se) ||
> +                 (rd->state.id.grbm.se != 0xFFFFFFFF && rd->state.id.grbm.se >= adev->gfx.config.max_shader_engines)) {
> +                     pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
> +                     pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
> +                     amdgpu_virt_disable_access_debugfs(adev);
> +                     return -EINVAL;
> +             }
> +             mutex_lock(&adev->grbm_idx_mutex);
> +             amdgpu_gfx_select_se_sh(adev, rd->state.id.grbm.se,
> +                                                             rd->state.id.grbm.sh,
> +                                                             rd->state.id.grbm.instance);
> +     }
> +
> +     if (rd->state.id.use_srbm) {
> +             mutex_lock(&adev->srbm_mutex);
> +             amdgpu_gfx_select_me_pipe_q(adev, rd->state.id.srbm.me, rd->state.id.srbm.pipe,
> +                                                                     rd->state.id.srbm.queue, rd->state.id.srbm.vmid);
> +     }
> +
> +     if (rd->state.id.pg_lock)
> +             mutex_lock(&adev->pm.mutex);
> +
> +     while (size) {
> +             if (!write_en) {
> +                     value = RREG32(rd->state.offset >> 2);
> +                     r = put_user(value, (uint32_t *)buf);
> +             } else {
> +                     r = get_user(value, (uint32_t *)buf);
> +                     if (!r)
> +                             amdgpu_mm_wreg_mmio_rlc(adev, rd->state.offset >> 2, value);
> +             }
> +             if (r) {
> +                     result = r;
> +                     goto end;
> +             }
> +             rd->state.offset += 4;
> +             size -= 4;
> +             result += 4;
> +             buf += 4;
> +     }
> +end:
> +     if (rd->state.id.use_grbm) {
> +             amdgpu_gfx_select_se_sh(adev, 0xffffffff, 0xffffffff, 0xffffffff);
> +             mutex_unlock(&adev->grbm_idx_mutex);
> +     }
> +
> +     if (rd->state.id.use_srbm) {
> +             amdgpu_gfx_select_me_pipe_q(adev, 0, 0, 0, 0);
> +             mutex_unlock(&adev->srbm_mutex);
> +     }
> +
> +     if (rd->state.id.pg_lock)
> +             mutex_unlock(&adev->pm.mutex);
> +
> +     // in umr (the likely user of this) flags are set per file operation
> +     // which means they're never "unset" explicitly.  To avoid breaking
> +     // this convention we unset the flags after each operation
> +     // flags are for a single call (need to be set for every read/write)
> +     rd->state.id.use_grbm = 0;
> +     rd->state.id.use_srbm = 0;
> +     rd->state.id.pg_lock  = 0;
> +
> +     pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
> +     pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
> +
> +     amdgpu_virt_disable_access_debugfs(adev);
> +     return result;
> +}
> +
> +static long amdgpu_debugfs_regs2_ioctl(struct file *f, unsigned int cmd, unsigned long data)
> +{
> +     struct amdgpu_debugfs_regs2_data *rd = f->private_data;
> +
> +     switch (cmd) {
> +     case AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE:
> +             if (copy_from_user(&rd->state.id, (struct amdgpu_debugfs_regs2_iocdata *)data, sizeof rd->state.id))
> +                     return -EINVAL;
> +             break;
> +     default:
> +             return -EINVAL;
> +     }
> +     return 0;
> +}
> +
> +static ssize_t amdgpu_debugfs_regs2_read(struct file *f, char __user *buf, size_t size, loff_t *pos)
> +{
> +     struct amdgpu_debugfs_regs2_data *rd = f->private_data;
> +     rd->state.offset = *pos;
> +     return amdgpu_debugfs_regs2_op(f, buf, size, 0);
> +}
> +
> +static ssize_t amdgpu_debugfs_regs2_write(struct file *f, const char __user *buf, size_t size, loff_t *pos)
> +{
> +     struct amdgpu_debugfs_regs2_data *rd = f->private_data;
> +     rd->state.offset = *pos;
> +     return amdgpu_debugfs_regs2_op(f, (char __user *)buf, size, 1);
> +}
> +
>   
>   /**
>    * amdgpu_debugfs_regs_pcie_read - Read from a PCIE register
> @@ -1091,6 +1241,16 @@ static ssize_t amdgpu_debugfs_gfxoff_read(struct file *f, char __user *buf,
>       return result;
>   }
>   
> +static const struct file_operations amdgpu_debugfs_regs2_fops = {
> +     .owner = THIS_MODULE,
> +     .unlocked_ioctl = amdgpu_debugfs_regs2_ioctl,
> +     .read = amdgpu_debugfs_regs2_read,
> +     .write = amdgpu_debugfs_regs2_write,
> +     .open = amdgpu_debugfs_regs2_open,
> +     .release = amdgpu_debugfs_regs2_release,
> +     .llseek = default_llseek
> +};
> +
>   static const struct file_operations amdgpu_debugfs_regs_fops = {
>       .owner = THIS_MODULE,
>       .read = amdgpu_debugfs_regs_read,
> @@ -1148,6 +1308,7 @@ static const struct file_operations amdgpu_debugfs_gfxoff_fops = {
>   
>   static const struct file_operations *debugfs_regs[] = {
>       &amdgpu_debugfs_regs_fops,
> +     &amdgpu_debugfs_regs2_fops,
>       &amdgpu_debugfs_regs_didt_fops,
>       &amdgpu_debugfs_regs_pcie_fops,
>       &amdgpu_debugfs_regs_smc_fops,
> @@ -1160,6 +1321,7 @@ static const struct file_operations *debugfs_regs[] = {
>   
>   static const char *debugfs_regs_names[] = {
>       "amdgpu_regs",
> +     "amdgpu_regs2",
>       "amdgpu_regs_didt",
>       "amdgpu_regs_pcie",
>       "amdgpu_regs_smc",
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
> index 141a8474e24f..ec044df5d428 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
> @@ -22,6 +22,8 @@
>    * OTHER DEALINGS IN THE SOFTWARE.
>    *
>    */
> +#include <linux/ioctl.h>
> +#include <uapi/drm/amdgpu_drm.h>
>   
>   /*
>    * Debugfs
> @@ -38,3 +40,33 @@ void amdgpu_debugfs_fence_init(struct amdgpu_device *adev);
>   void amdgpu_debugfs_firmware_init(struct amdgpu_device *adev);
>   void amdgpu_debugfs_gem_init(struct amdgpu_device *adev);
>   int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev);
> +
> +/*
> + * MMIO debugfs IOCTL structure
> + */
> +struct amdgpu_debugfs_regs2_iocdata {
> +     __u8 use_srbm, use_grbm, pg_lock;

You should consider using u32 here as well or add explicitly padding.

> +     struct {
> +             __u32 se, sh, instance;
> +     } grbm;
> +     struct {
> +             __u32 me, pipe, queue, vmid;
> +     } srbm;
> +};
> +
> +/*
> + * MMIO debugfs state data (per file* handle)
> + */
> +struct amdgpu_debugfs_regs2_data {
> +     struct amdgpu_device *adev;
> +     struct {
> +             struct amdgpu_debugfs_regs2_iocdata id;
> +             __u32 offset;

What is the offset good for here?

Regards,
Christian.

> +     } state;
> +};
> +
> +enum AMDGPU_DEBUGFS_REGS2_CMDS {
> +     AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE=0,
> +};
> +
> +#define AMDGPU_DEBUGFS_REGS2_IOC_SET_STATE _IOWR(0x20, AMDGPU_DEBUGFS_REGS2_CMD_SET_STATE, struct amdgpu_debugfs_regs2_iocdata)




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