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

[Borislav Petkov]

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.

> [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.

>  	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.

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

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette