STRUCT EADM_SCSW(9)

📦 version 7.3.1, in nixpkgs unstable

💅 struct eadm_scsw — the whole vibe check

okay so this is from the Kernel API Manual, section 9, and it's literally the page for struct eadm_scsw. bestie, it's giving "tiny struct, big responsibility" and i'm obsessed 🫶

✨ NAME ✨

struct eadm_scsw — the subchannel status word for eadm subchannels. that's it, that's the whole name. iconic behavior, no notes 💅

🌸 SYNOPSIS 🌸

here's the actual shape of it, copy-paste vibes, don't touch a single character:

struct eadm_scsw {
    u32 key:4;
    u32:1;
    u32 eswf:1;
    u32 cc:2;
    u32:6;
    u32 ectl:1;
    u32:2;
    u32 fctl:3;
    u32 actl:7;
    u32 stctl:5;
    dma32_t aob;
    u32 dstat:8;
    u32 cstat:8;
    u32:16;
 };

and yes, those unnamed ones (u32:1;, u32:6;, u32:2; and that u32:16; at the end) are just padding bits sitting there with no member name and no description. they're the silent background characters of this struct, and honestly? main character energy anyway ✨

🎀 Members 🎀

okay so every single one of these, in order, no skipping 👑

  • key — the subchannel key 🔑
  • eswf — the esw format
  • cc — the deferred condition code
  • ectl — extended control
  • fctl — function control
  • actl — activity control
  • stctl — status control
  • aob — the AOB address (this one's a dma32_t, not a bitfield, so it gets a whole field to itself, slay)
  • dstat — device status
  • cstat — subchannel status

that's literally it, ten named members and a bunch of padding, and we stan a compact struct 🧚

🦋 SEE ALSO 🦋

so there's a LOT of friends in this friend group. the kernel file is ./arch/s390/include/asm/scsw.h, and like, every sibling struct and every scsw_* helper you could possibly want is listed here. buckle up bestie, this is a long one 😭

structs & unions first:

  • struct cmd_scsw(9)
  • struct tm_scsw(9)
  • union scsw(9)

the plain accessors:

the scsw_cmd_is_valid_* crew (yes, all of them):

then the scsw_tm_is_valid_* girlies:

and the general scsw_is_valid_* set:

aaand the solicited checks to close it out:

ok real talk, this list is LONG but it's not filler — every one of those is a genuine SEE ALSO reference from the original page, so if you need the full picture of scsw handling, this is your group chat 💜

and that's the page!! 🎀 this whole thing lives in ./arch/s390/include/asm, dated October 2026, straight out of the Kernel API Manual — so like, cite it cute when you quote it, mwah 💖 🦋

📦 where this page comes from