26bca020b6
Nexoniarz is the sole author and SchOS was never published under Apache-2.0, so this is a straight relicence. LICENSE is the FSF GPLv2 text, every first-party SPDX header moves to GPL-2.0-or-later, and NOTICE, README.md, docs/licensing.md and the site say so. projects/schfs-linux follows the rest of the tree. The GPL gives copyleft: a fork has to ship its source. It also lifts the old "Linux drivers, never" rule, since GPL-2.0-only code combines with GPL-2.0-or-later. "Or later" leaves room for GPLv3, but one binary still has to pick one version, so docs/licensing.md now keeps Apache-2.0 and GPLv3 code out of the kernel to keep Linux code possible there. BSD 4-clause code goes from "avoid" to "no", because the advertising clause is GPL-incompatible. LDLS still ships no .ko. That boundary is now project policy rather than a legal requirement, and ldls.md, devices.md and licensing.md section 6 say so. refmod declares license=GPL, and ldls-check passes (27 checks). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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//
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// Register access. See ldls/kpi/kpi.h for the provenance rule.
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//
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// These are the busiest symbols by a wide margin -- 538 of 8139too's 552 probe
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// calls are two of them -- and they are also the shortest, because once a BAR
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// is mapped a register access *is* a memory access. The whole of what these
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// add over a plain dereference is the `volatile`, which stops a compiler
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// deciding that reading the same address twice is redundant. For a status
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// register, reading it twice is the entire point.
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//
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// The argument order is worth noting because it is the opposite of what a C
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// programmer expects and getting it backwards produces something that almost
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// works: Linux's writes take the **value first** and the address second.
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#include "types.h"
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#include "kpi.h"
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// Every access is checked against the mapping `pci_iomap` returned.
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//
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// A driver that reaches outside its own BAR would otherwise take the process
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// down with a page fault, and the report would be an address with no context.
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// This turns that into a line naming the offset it wanted -- and since there
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// is no IOMMU, a hosted driver's stray accesses are exactly the class of thing
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// that has to be noticed early or not at all.
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int
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kpi_io_ok(void *addr, int width, int write)
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{
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unsigned long a = (unsigned long)addr;
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if (kpi.io_base && a >= kpi.io_base &&
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a + (unsigned long)width <= kpi.io_base + kpi.io_len)
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return 1;
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kpi.io_stray++;
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if (kpi.io_stray <= 8) {
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kpi_log(" kpi: the driver tried to ");
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kpi_log(write ? "write " : "read ");
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kpi_lognum(width);
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kpi_log(" byte(s) at 0x");
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kpi_loghex(a, 16);
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if (kpi.io_base && a < kpi.io_base) {
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kpi_log(", which is ");
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kpi_lognum((long long)(kpi.io_base - a));
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kpi_log(" below the mapping");
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} else if (kpi.io_base) {
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kpi_log(", which is past the end of the mapping");
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} else {
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kpi_log(", but nothing is mapped yet");
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}
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kpi_log("\n");
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}
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return 0;
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}
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unsigned char
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kpi_ioread8(void *addr)
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{
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if (!kpi_io_ok(addr, 1, 0)) return 0xff;
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return *(volatile unsigned char *)addr;
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}
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unsigned short
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kpi_ioread16(void *addr)
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{
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if (!kpi_io_ok(addr, 2, 0)) return 0xffff;
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return *(volatile unsigned short *)addr;
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}
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unsigned int
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kpi_ioread32(void *addr)
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{
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if (!kpi_io_ok(addr, 4, 0)) return 0xffffffff;
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return *(volatile unsigned int *)addr;
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}
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void
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kpi_iowrite8(unsigned char v, void *addr)
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{
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if (!kpi_io_ok(addr, 1, 1)) return;
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*(volatile unsigned char *)addr = v;
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}
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void
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kpi_iowrite16(unsigned short v, void *addr)
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{
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if (!kpi_io_ok(addr, 2, 1)) return;
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*(volatile unsigned short *)addr = v;
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}
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void
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kpi_iowrite32(unsigned int v, void *addr)
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{
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if (!kpi_io_ok(addr, 4, 1)) return;
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*(volatile unsigned int *)addr = v;
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}
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