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arch/x86/acpigen: Fix corner case in _ROM generator 

In case the Option ROM isn't a multiple of 4KiB the last buffer was
truncated to prevent a buffer overrun. But tests on nouveau showed
that nouveau expects a buffer that has the requested size and is zero
padded instead.

Always return a buffer with requested size and zero pad the remaining
bytes. Fixes nouveau on Lenovo W520 with Option ROM not being multiple
of 4 KiB.

Change-Id: I3f0ecc42a21945f66eb67f73e511bd516acf0fa9
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/25999
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Rikken <nico@nicorikken.eu>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Naresh Solanki <naresh.solanki@intel.com>
This commit is contained in:
Patrick Rudolph 2018-05-02 19:07:57 +02:00 committed by Patrick Georgi
parent 892e9f6030
commit 65cbbe77ac
1 changed files with 14 additions and 3 deletions
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17
src/arch/x86/acpigen.c
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@ -1342,6 +1342,10 @@ void acpigen_write_dsm_uuid_arr(struct dsm_uuid *ids, size_t count)
* Generate ACPI AML code for _ROM method.
* This function takes as input ROM data and ROM length.
*
* The ACPI spec isn't clear about what should happen at the end of the
* ROM. Tests showed that it shouldn't truncate, but fill the remaining
* bytes in the returned buffer with zeros.
*
* Arguments passed into _DSM method:
* Arg0 = Offset in Bytes
* Arg1 = Bytes to return
@ -1367,6 +1371,8 @@ void acpigen_write_dsm_uuid_arr(struct dsm_uuid *ids, size_t count)
* Store (0x1000, Local1)
* }
*
* Store (Local1, Local3)
*
* If (LGreater (Local0, 0x10000))
* {
* Return(Buffer(Local1){0})
@ -1381,7 +1387,7 @@ void acpigen_write_dsm_uuid_arr(struct dsm_uuid *ids, size_t count)
* }
* }
*
* Name (ROM1, Buffer (Local1) {0})
* Name (ROM1, Buffer (Local3) {0})
*
* Multiply (Local0, 0x08, Local0)
* Multiply (Local1, 0x08, Local1)
@ -1443,6 +1449,11 @@ void acpigen_write_rom(void *bios, const size_t length)
/* Pop if */
acpigen_pop_len();
/* Store (Local1, Local3) */
acpigen_write_store();
acpigen_emit_byte(LOCAL1_OP);
acpigen_emit_byte(LOCAL3_OP);
/* If (LGreater (Local0, length)) */
acpigen_write_if();
acpigen_emit_byte(LGREATER_OP);
@ -1489,11 +1500,11 @@ void acpigen_write_rom(void *bios, const size_t length)
/* Pop if */
acpigen_pop_len();
/* Name (ROM1, Buffer (Local1) {0}) */
/* Name (ROM1, Buffer (Local3) {0}) */
acpigen_write_name("ROM1");
acpigen_emit_byte(BUFFER_OP);
acpigen_write_len_f();
acpigen_emit_byte(LOCAL1_OP);
acpigen_emit_byte(LOCAL3_OP);
acpigen_emit_byte(0);
acpigen_pop_len();