Re: [PATCH v7 2/3] RAS/AMD/ATL: Translate UMC normalized address to DRAM address using PRM

[Yazen Ghannam]

On Mon, Jul 06, 2026 at 05:32:04PM -0700, Borislav Petkov wrote:
> On Tue, Jun 30, 2026 at 05:06:39PM -0400, Yazen Ghannam wrote:
> > From: Avadhut Naik <avadhut.naik@xxxxxxx>
> > 
> > Modern AMD SOCs provide UEFI PRM module that implements various address
> > translation PRM handlers.[1] These handlers can be invoked by the OS or
> > hypervisor at runtime to perform address translations.
> > 
> > On AMD's Zen-based SOCs, Unified Memory Controller (UMC) relative
> > "normalized" address is reported through MCA_ADDR of UMC SMCA bank type
> > on occurrence of a DRAM ECC error. This address must be converted into
> > system physical address and DRAM address to export additional information
> > about the error.
> > 
> > Add support to convert normalized address into DRAM address through the
> > appropriate PRM handler. Instead of logging the translated DRAM address
> > locally, export the translating function when the Address Translation
> > library is initialized. Modules like amd64_edac can then invoke the PRM
> > handler to add the DRAM address to their error records. Additionally, it
> > can also be exported through the RAS tracepont.
> 
> Use this commit message for this patch:
> 
>     Modern AMD SOCs provide an UEFI PRM module that implements various address
>     translation PRM handlers¹. These handlers can be invoked by the OS or
>     the hypervisor at runtime to perform address translations.
>     
>     On AMD's Zen-based SOCs, a Unified Memory Controller (UMC) relative
>     "normalized" address is reported through the MCA_ADDR of UMC SMCA banks
>     on occurrence of a DRAM ECC error. This address must be converted into
>     a system physical address and DRAM address in order to decode additional
>     information about the error.
>     
>     Add support to convert a normalized address into a DRAM address using
>     such PRM handler.
>     
>     ¹https://bugzilla.kernel.org/show_bug.cgi?id=220577
> 
> or run it through AI because I'm tired of adding pronouns left and right and
> removing text which regurgitates the code in the patch.
> 

Okay.

> > [1] https://bugzilla.kernel.org/show_bug.cgi?id=220577
> > 
> > [Yazen: Remove 'handler available' check]
> > 
> > Signed-off-by: Avadhut Naik <avadhut.naik@xxxxxxx>
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> > ---
> >  drivers/ras/amd/atl/core.c     |  6 ++++++
> >  drivers/ras/amd/atl/internal.h | 11 ++++++++++-
> >  drivers/ras/amd/atl/prm.c      | 32 ++++++++++++++++++++++++++++----
> >  drivers/ras/amd/atl/system.c   |  3 +++
> >  drivers/ras/amd/atl/umc.c      |  9 +++++++++
> >  include/linux/ras.h            | 14 ++++++++++++++
> >  6 files changed, 70 insertions(+), 5 deletions(-)
> 
> ...
> 
> > +static inline int prm_umc_norm_to_dram_addr(u8 socket_id, u64 bank_id,
> > +					    unsigned long addr, struct atl_dram_addr *dram_addr)
> 
> ... int prm_umc_norm_to_dram_addr(u8 socket_id, u64 bank_id, unsigned long addr,
> 				  struct atl_dram_addr *dram_addr)
> 
> > +{
> > +	return -ENODEV;
> > +}
> > +#endif
> >  /*
> >   * Make a gap in @data that is @num_bits long starting at @bit_num.
> >   * e.g. data		= 11111111'b
> > diff --git a/drivers/ras/amd/atl/prm.c b/drivers/ras/amd/atl/prm.c
> > index 0f9bfa96e16a..c69158f66639 100644
> > --- a/drivers/ras/amd/atl/prm.c
> > +++ b/drivers/ras/amd/atl/prm.c
> > @@ -19,10 +19,11 @@
> >  #include <linux/prmt.h>
> >  
> >  /*
> > - * PRM parameter buffer - normalized to system physical address, as described
> > - * in the "PRM Parameter Buffer" section of the AMD ACPI Porting Guide.
> > + * PRM parameter buffer - normalized to system physical address and normalized
> > + * to DRAM address, as described in the "PRM Parameter Buffer" section of the
> > + * AMD ACPI Porting Guide.
> >   */
> > -struct norm_to_sys_param_buf {
> > +struct prm_parameter_buffer {
> 
> struct param_buf {
> 
> This is not BIOS code.
> 

Okay.

> >  	u64 norm_addr;
> >  	u8 socket;
> >  	u64 bank_id;
> > @@ -31,7 +32,7 @@ struct norm_to_sys_param_buf {
> >  
> >  unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 bank_id, unsigned long addr)
> >  {
> > -	struct norm_to_sys_param_buf p_buf;
> > +	struct prm_parameter_buffer p_buf;
> >  	unsigned long ret_addr;
> >  	int ret;
> >  
> > @@ -51,3 +52,26 @@ unsigned long prm_umc_norm_to_sys_addr(u8 socket_id, u64 bank_id, unsigned long
> >  
> >  	return ret;
> >  }
> > +
> > +int prm_umc_norm_to_dram_addr(u8 socket_id, u64 bank_id,
> > +			      unsigned long addr, struct atl_dram_addr *dram_addr)
> 
> int prm_umc_norm_to_dram_addr(u8 socket_id, u64 bank_id, unsigned long addr,
> 			      struct atl_dram_addr *dram_addr)
> 
> > +{
> > +	struct prm_parameter_buffer p_buf;
> > +	int ret;
> > +
> > +	p_buf.norm_addr	= addr;
> > +	p_buf.socket	= socket_id;
> > +	p_buf.bank_id	= bank_id;
> > +	p_buf.out_buf	= dram_addr;
> > +
> > +	ret = acpi_call_prm_handler(norm_to_dram_guid, &p_buf);
> > +	if (!ret)
> > +		return ret;
> > +
> > +	if (ret == -ENODEV)
> > +		pr_debug("PRM module/handler not available.\n");
> > +	else
> > +		pr_notice_once("PRM DRAM Address Translation failed.\n");
> 
> Dump ret here.

What do you mean? Print it or remove it?

> 
> Also, this function is an almost identical copy to prm_umc_norm_to_sys_addr().
> Merge the two pls.
> 

Okay, will do.

Thanks,
Yazen