The alignment constraint is defined in the CSM specifications as "Bit mapped. First non-zero bit from the right is the alignment."
Use __fls() to sanitise the alignment given that definition, since passing a non-power-of-two alignment to _malloc() isn't going to work well. And cope with being passed zero, which was happening for the E820 table allocation from EDK2.
Signed-off-by: David Woodhouse dwmw2@infradead.org --- v2: Enforce MALLOC_MIN_ALIGN
src/fw/csm.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/src/fw/csm.c b/src/fw/csm.c index 03b4bb8..3fcc252 100644 --- a/src/fw/csm.c +++ b/src/fw/csm.c @@ -258,11 +258,21 @@ handle_csm_0006(struct bregs *regs) u16 region = regs->bx; // (1 for F000 seg, 2 for E000 seg, 0 for either) void *chunk = NULL;
+ dprintf(3, "Legacy16GetTableAddress size %x align %x region %d\n", + size, align, region); + if (!region) region = 3;
- dprintf(3, "Legacy16GetTableAddress size %x align %x region %d\n", - size, align, region); + // DX = Required address alignment. Bit mapped. + // First non-zero bit from the right is the alignment.*/ + if (align) { + align = 1 << __ffs(align); + if (align < MALLOC_MIN_ALIGN) + align = MALLOC_MIN_ALIGN; + } else { + align = MALLOC_MIN_ALIGN; + }
if (region & 2) chunk = _malloc(&ZoneLow, size, align);