[M] Change in coreboot[main]: acpi/acpigen: Increase max package length for acpigen_pop_len()

[Matt DeVillier (Code Review)]

Matt DeVillier has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/84192?usp=email )

Change subject: acpi/acpigen: Increase max package length for acpigen_pop_len()
......................................................................

acpi/acpigen: Increase max package length for acpigen_pop_len()

The AML spec allows for up to 4 bytes to be used to encode the package
length, so adjust acpigen_pop_len() to accommodate that now that we're
running up against the packaged size limit available when only 3 bytes
are used to encode the length.

Change-Id: I8f72fa84cfdae480fec42b0968bd7cefcdb96bdc
Signed-off-by: Matt DeVillier 
---
M src/acpi/acpigen.c
1 file changed, 35 insertions(+), 16 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/92/84192/1

diff --git a/src/acpi/acpigen.c b/src/acpi/acpigen.c
index 4049df0..d6b652e 100644
--- a/src/acpi/acpigen.c
+++ b/src/acpi/acpigen.c
@@ -4,7 +4,7 @@
 #define ACPIGEN_LENSTACK_SIZE 10

/* If you need to change this, change acpigen_pop_len too */
-#define ACPIGEN_RSVD_PKGLEN_BYTES	3
+#define ACPIGEN_RSVD_PKGLEN_BYTES	4

#include <lib.h>
 #include <string.h>
@@ -42,13 +42,13 @@

if (len <= 0x3f + 2) {
    	/* PkgLength of up to 0x3f can be encoded in one PkgLength byte instead of the
-		   reserved 3 bytes. Since only 1 PkgLength byte will be written, the payload
-		   data needs to be moved by 2 bytes */
-		memmove(&p[ACPIGEN_RSVD_PKGLEN_BYTES - 2],
+		   reserved 4 bytes. Since only 1 PkgLength byte will be written, the payload
+		   data needs to be moved by 3 bytes */
+		memmove(&p[ACPIGEN_RSVD_PKGLEN_BYTES - 3],
    		&p[ACPIGEN_RSVD_PKGLEN_BYTES], payload_len);
-		/* Adjust the PkgLength to take into account that we only use 1 of the 3
+		/* Adjust the PkgLength to take into account that we only use 1 of the 4
    	   reserved bytes */
-		len -= 2;
+		len -= 3;
    	/* The two most significant bits of PkgLength get the value of 0 to indicate
    	   there are no additional PkgLength bytes. In this case the single PkgLength
    	   byte encodes the length in its lower 6 bits */
@@ -57,13 +57,13 @@
    	acpigen_set_current(p + len);
    } else if (len <= 0xfff + 1) {
    	/* PkgLength of up to 0xfff can be encoded in 2 PkgLength bytes instead of the
-		   reserved 3 bytes. Since only 2 PkgLength bytes will be written, the payload
-		   data needs to be moved by 1 byte */
-		memmove(&p[ACPIGEN_RSVD_PKGLEN_BYTES - 1],
+		   reserved 4 bytes. Since only 2 PkgLength bytes will be written, the payload
+		   data needs to be moved by 2 bytes */
+		memmove(&p[ACPIGEN_RSVD_PKGLEN_BYTES - 2],
    		&p[ACPIGEN_RSVD_PKGLEN_BYTES], payload_len);
-		/* Adjust the PkgLength to take into account that we only use 2 of the 3
+		/* Adjust the PkgLength to take into account that we only use 2 of the 4
    	   reserved bytes */
-		len -= 1;
+		len -= 2;
    	/* The two most significant bits of PkgLength get the value of 1 to indicate
    	   there's a second PkgLength byte. The lower 4 bits of the first PkgLength
    	   byte and the second PkgLength byte encode the length */
@@ -72,19 +72,38 @@
    	/* Adjust pointer for next ACPI bytecode byte */
    	acpigen_set_current(p + len);
    } else if (len <= 0xfffff) {
-		/* PkgLength of up to 0xfffff can be encoded in 3 PkgLength bytes. Since this
-		   is the amount of reserved bytes, no need to move the payload in this case */
-		/* The two most significant bits of PkgLength get the value of 2 to indicate
-		   there are two more PkgLength bytes following the first one. The lower 4 bits
+		/* PkgLength of up to 0xfffff can be encoded in 3 PkgLength bytes instead of the
+		   reserved 4 bytes. Since only 3 PkgLength bytes will be written, the payload
+		   data needs to be moved by 1 byte */
+		memmove(&p[ACPIGEN_RSVD_PKGLEN_BYTES - 1],
+			&p[ACPIGEN_RSVD_PKGLEN_BYTES], payload_len);
+		/* Adjust the PkgLength to take into account that we only use 3 of the 4
+		   reserved bytes */
+		len -= 1;
+		/* The two most significant bits of PkgLength get the value of 3 to indicate
+		   there are three more PkgLength bytes following the first one. The lower 4 bits
    	   of the first PkgLength byte and the two following PkgLength bytes encode the
    	   length */
    	p[0] = (0x2 << 6 | (len & 0xf));
    	p[1] = (len >> 4 & 0xff);
    	p[2] = (len >> 12 & 0xff);
+		/* Adjust pointer for next ACPI bytecode byte */
+		acpigen_set_current(p + len);
+	} else if (len <= 0xfffffff) {
+		/* PkgLength of up to 0xfffffff can be encoded in 3 PkgLength bytes. Since this
+		   is the amount of reserved bytes, no need to move the payload in this case */
+		/* The two most significant bits of PkgLength get the value of 2 to indicate
+		   there are two more PkgLength bytes following the first one. The lower 4 bits
+		   of the first PkgLength byte and the two following PkgLength bytes encode the
+		   length */
+		p[0] = (0x3 << 6 | (len & 0xf));
+		p[1] = (len >> 4 & 0xff);
+		p[2] = (len >> 12 & 0xff);
+		p[3] = (len >> 20 & 0xff);
    	/* No need to adjust pointer for next ACPI bytecode byte */
    } else {
    	/* The case of PkgLength up to 0xfffffff isn't supported at the moment */
-		printk(BIOS_ERR, "%s: package length exceeds maximum of 0xfffff.\n", __func__);
+		printk(BIOS_ERR, "%s: package length exceeds maximum of 0xfffffff.\n", __func__);
    }
 }