Messages in this thread Patch in this message | | | Date | Wed, 30 Jun 2021 19:17:41 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 05/31] EDAC/amd64: Add context struct |
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On Wed, Jun 23, 2021 at 07:19:36PM +0000, Yazen Ghannam wrote: > Define an address translation context struct. This will hold values that > will be passed between multiple functions. > > Save return address, Node ID, and the Instance ID number to start. > Currently, we use the UMC number as the Instance ID, but future DF
Please use passive voice in your commit message: no "we" or "I", etc.
And this here is a perfect example: it sounds here like "we" is "AMD" but we use "we" mostly for the kernel. And there's the confusion.
So please teach yourself to formulate those commit messages properly - the future you will thank you, trust me!
:-)
> versions may use another value. > > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> > --- > Link: > https://lkml.kernel.org/r/20210507190140.18854-3-Yazen.Ghannam@amd.com > > v1->v2: > * Moved from arch/x86 to EDAC. > * Changed "umc" variable to "inst_id". > * Drop df_types enum. > > drivers/edac/amd64_edac.c | 49 +++++++++++++++++++++++++-------------- > 1 file changed, 31 insertions(+), 18 deletions(-) > > diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c > index d67cd8f57b94..62eca188458f 100644 > --- a/drivers/edac/amd64_edac.c > +++ b/drivers/edac/amd64_edac.c > @@ -1079,12 +1079,15 @@ static struct df_reg df_regs[] = { > [SYS_FAB_ID_MASK] = {1, 0x208}, > }; > > +struct addr_ctx { > + u64 ret_addr; > + u16 nid; > + u8 inst_id; > +}; > + > static int umc_normaddr_to_sysaddr(u64 norm_addr, u16 nid, u8 umc, u64 *sys_addr) > { > u64 dram_base_addr, dram_limit_addr, dram_hole_base; > - /* We start from the normalized address */ > - u64 ret_addr = norm_addr; > - > u32 tmp; > > u8 die_id_shift, die_id_mask, socket_id_shift, socket_id_mask; > @@ -1097,6 +1100,16 @@ static int umc_normaddr_to_sysaddr(u64 norm_addr, u16 nid, u8 umc, u64 *sys_addr > > struct df_reg reg; > > + struct addr_ctx ctx;
Those empty-lines spaced-out local vars look weird.
> + memset(&ctx, 0, sizeof(ctx)); > + > + /* We start from the normalized address */ > + ctx.ret_addr = norm_addr; > + > + ctx.nid = nid; > + ctx.inst_id = umc; > + > if (amd_df_indirect_read(nid, df_regs[DRAM_OFFSET], umc, &tmp)) > goto out_err; > > @@ -1105,7 +1118,7 @@ static int umc_normaddr_to_sysaddr(u64 norm_addr, u16 nid, u8 umc, u64 *sys_addr > u64 hi_addr_offset = (tmp & GENMASK_ULL(31, 20)) << 8; > > if (norm_addr >= hi_addr_offset) { > - ret_addr -= hi_addr_offset; > + ctx.ret_addr -= hi_addr_offset; > base = 1; > } > } > @@ -1236,14 +1249,14 @@ static int umc_normaddr_to_sysaddr(u64 norm_addr, u16 nid, u8 umc, u64 *sys_addr > * bits there are. "intlv_addr_bit" tells us how many "Y" bits > * there are (where "I" starts). > */ > - temp_addr_y = ret_addr & GENMASK_ULL(intlv_addr_bit-1, 0); > + temp_addr_y = ctx.ret_addr & GENMASK_ULL(intlv_addr_bit - 1, 0); > temp_addr_i = (cs_id << intlv_addr_bit); > - temp_addr_x = (ret_addr & GENMASK_ULL(63, intlv_addr_bit)) << num_intlv_bits; > - ret_addr = temp_addr_x | temp_addr_i | temp_addr_y; > + temp_addr_x = (ctx.ret_addr & GENMASK_ULL(63, intlv_addr_bit)) << num_intlv_bits; > + ctx.ret_addr = temp_addr_x | temp_addr_i | temp_addr_y;
You want to align those vertically on the "=" for better readability.
> } > > /* Add dram base address */ > - ret_addr += dram_base_addr; > + ctx.ret_addr += dram_base_addr; > > /* If legacy MMIO hole enabled */ > if (lgcy_mmio_hole_en) { > @@ -1251,29 +1264,29 @@ static int umc_normaddr_to_sysaddr(u64 norm_addr, u16 nid, u8 umc, u64 *sys_addr > goto out_err; > > dram_hole_base = tmp & GENMASK(31, 24); > - if (ret_addr >= dram_hole_base) > - ret_addr += (BIT_ULL(32) - dram_hole_base); > + if (ctx.ret_addr >= dram_hole_base) > + ctx.ret_addr += (BIT_ULL(32) - dram_hole_base); > } > > if (hash_enabled) { > /* Save some parentheses and grab ls-bit at the end. */ > - hashed_bit = (ret_addr >> 12) ^ > - (ret_addr >> 18) ^ > - (ret_addr >> 21) ^ > - (ret_addr >> 30) ^ > + hashed_bit = (ctx.ret_addr >> 12) ^ > + (ctx.ret_addr >> 18) ^ > + (ctx.ret_addr >> 21) ^ > + (ctx.ret_addr >> 30) ^ > cs_id; > > hashed_bit &= BIT(0); > > - if (hashed_bit != ((ret_addr >> intlv_addr_bit) & BIT(0))) > - ret_addr ^= BIT(intlv_addr_bit); > + if (hashed_bit != ((ctx.ret_addr >> intlv_addr_bit) & BIT(0))) > + ctx.ret_addr ^= BIT(intlv_addr_bit); > } > > /* Is calculated system address is above DRAM limit address? */ > - if (ret_addr > dram_limit_addr) > + if (ctx.ret_addr > dram_limit_addr) > goto out_err; > > - *sys_addr = ret_addr; > + *sys_addr = ctx.ret_addr;
So adding ctx to exchange data between functions - that was a good idea.
But what this patch does is pointless because you simply replace those variables with a local struct.
I guess the aha moment will come with the later patches when you start passing it around to functions.
/me waits to see.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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