[acpi] Remove userptr_t from ACPI table parsing

Simplify the ACPI table parsing code by assuming that all table
content is fully accessible via pointer dereferences.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/x86/interface/pcbios/acpi_timer.c

@@ -102,20 +102,19 @@ static void acpi_udelay ( unsigned long usecs ) {
  * @ret rc		Return status code
  */
 static int acpi_timer_probe ( void ) {
-	struct acpi_fadt fadtab;
-	userptr_t fadt;
+	const struct acpi_fadt *fadt;
 	unsigned int pm_tmr_blk;
 
 	/* Locate FADT */
-	fadt = acpi_table ( FADT_SIGNATURE, 0 );
+	fadt = container_of ( acpi_table ( FADT_SIGNATURE, 0 ),
+			      struct acpi_fadt, acpi );
 	if ( ! fadt ) {
 		DBGC ( &acpi_timer, "ACPI could not find FADT\n" );
 		return -ENOENT;
 	}
 
 	/* Read FADT */
-	copy_from_user ( &fadtab, fadt, 0, sizeof ( fadtab ) );
-	pm_tmr_blk = le32_to_cpu ( fadtab.pm_tmr_blk );
+	pm_tmr_blk = le32_to_cpu ( fadt->pm_tmr_blk );
 	if ( ! pm_tmr_blk ) {
 		DBGC ( &acpi_timer, "ACPI has no timer\n" );
 		return -ENOENT;

src/arch/x86/interface/pcbios/acpipwr.c

@@ -62,8 +62,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  * uglier hacks I have ever implemented, but it's still prettier than
  * the ACPI specification itself.
  */
-static int acpi_extract_sx ( userptr_t zsdt, size_t len, size_t offset,
-			     void *data ) {
+static int acpi_extract_sx ( const struct acpi_header *zsdt, size_t len,
+			     size_t offset, void *data ) {
 	unsigned int *sx = data;
 	uint8_t bytes[4];
 	uint8_t *byte;
@@ -77,7 +77,8 @@ static int acpi_extract_sx ( userptr_t zsdt, size_t len, size_t offset,
 	}
 
 	/* Read first four bytes of value */
-	copy_from_user ( bytes, zsdt, offset, sizeof ( bytes ) );
+	memcpy ( bytes, ( ( ( const void * ) zsdt ) + offset ),
+		 sizeof ( bytes ) );
 	DBGC ( colour, "ACPI found \\_Sx containing %02x:%02x:%02x:%02x\n",
 	       bytes[0], bytes[1], bytes[2], bytes[3] );
 
@@ -111,8 +112,7 @@ static int acpi_extract_sx ( userptr_t zsdt, size_t len, size_t offset,
  * @ret rc		Return status code
  */
 int acpi_poweroff ( void ) {
-	struct acpi_fadt fadtab;
-	userptr_t fadt;
+	const struct acpi_fadt *fadt;
 	unsigned int pm1a_cnt_blk;
 	unsigned int pm1b_cnt_blk;
 	unsigned int pm1a_cnt;
@@ -123,16 +123,16 @@ int acpi_poweroff ( void ) {
 	int rc;
 
 	/* Locate FADT */
-	fadt = acpi_table ( FADT_SIGNATURE, 0 );
+	fadt = container_of ( acpi_table ( FADT_SIGNATURE, 0 ),
+			      struct acpi_fadt, acpi );
 	if ( ! fadt ) {
 		DBGC ( colour, "ACPI could not find FADT\n" );
 		return -ENOENT;
 	}
 
 	/* Read FADT */
-	copy_from_user ( &fadtab, fadt, 0, sizeof ( fadtab ) );
-	pm1a_cnt_blk = le32_to_cpu ( fadtab.pm1a_cnt_blk );
-	pm1b_cnt_blk = le32_to_cpu ( fadtab.pm1b_cnt_blk );
+	pm1a_cnt_blk = le32_to_cpu ( fadt->pm1a_cnt_blk );
+	pm1b_cnt_blk = le32_to_cpu ( fadt->pm1b_cnt_blk );
 	pm1a_cnt = ( pm1a_cnt_blk + ACPI_PM1_CNT );
 	pm1b_cnt = ( pm1b_cnt_blk + ACPI_PM1_CNT );
 

src/arch/x86/interface/pcbios/rsdp.c

@@ -53,50 +53,51 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @v start		Start address to search
  * @v len		Length to search
- * @ret rsdt		ACPI root system description table, or UNULL
+ * @ret rsdt		ACPI root system description table, or NULL
  */
-static userptr_t rsdp_find_rsdt_range ( userptr_t start, size_t len ) {
+static const struct acpi_rsdt * rsdp_find_rsdt_range ( const void *start,
+						       size_t len ) {
 	static const char signature[8] = RSDP_SIGNATURE;
-	struct acpi_rsdp rsdp;
-	userptr_t rsdt;
+	const struct acpi_rsdp *rsdp;
+	const struct acpi_rsdt *rsdt;
 	size_t offset;
 	uint8_t sum;
 	unsigned int i;
 
 	/* Search for RSDP */
-	for ( offset = 0 ; ( ( offset + sizeof ( rsdp ) ) < len ) ;
+	for ( offset = 0 ; ( ( offset + sizeof ( *rsdp ) ) < len ) ;
 	      offset += RSDP_STRIDE ) {
 
 		/* Check signature and checksum */
-		copy_from_user ( &rsdp, start, offset, sizeof ( rsdp ) );
-		if ( memcmp ( rsdp.signature, signature,
+		rsdp = ( start + offset );
+		if ( memcmp ( rsdp->signature, signature,
 			      sizeof ( signature ) ) != 0 )
 			continue;
-		for ( sum = 0, i = 0 ; i < sizeof ( rsdp ) ; i++ )
-			sum += *( ( ( uint8_t * ) &rsdp ) + i );
+		for ( sum = 0, i = 0 ; i < sizeof ( *rsdp ) ; i++ )
+			sum += *( ( ( uint8_t * ) rsdp ) + i );
 		if ( sum != 0 )
 			continue;
 
 		/* Extract RSDT */
-		rsdt = phys_to_virt ( le32_to_cpu ( rsdp.rsdt ) );
+		rsdt = phys_to_virt ( le32_to_cpu ( rsdp->rsdt ) );
 		DBGC ( rsdt, "RSDT %#08lx found via RSDP %#08lx\n",
 		       virt_to_phys ( rsdt ),
 		       ( virt_to_phys ( start ) + offset ) );
 		return rsdt;
 	}
 
-	return UNULL;
+	return NULL;
 }
 
 /**
  * Locate ACPI root system description table
  *
- * @ret rsdt		ACPI root system description table, or UNULL
+ * @ret rsdt		ACPI root system description table, or NULL
  */
-static userptr_t rsdp_find_rsdt ( void ) {
-	static userptr_t rsdt;
+static const struct acpi_rsdt * rsdp_find_rsdt ( void ) {
+	static const struct acpi_rsdt *rsdt;
+	const void *ebda;
 	uint16_t ebda_seg;
-	userptr_t ebda;
 	size_t ebda_len;
 
 	/* Return existing RSDT if already found */
@@ -119,7 +120,7 @@ static userptr_t rsdp_find_rsdt ( void ) {
 	if ( rsdt )
 		return rsdt;
 
-	return UNULL;
+	return NULL;
 }
 
 PROVIDE_ACPI ( rsdp, acpi_find_rsdt, rsdp_find_rsdt );