riscv: add physical memory protection (PMP) support

These codes are written by me based on the privileged instruction set.
I tested it by qemu/riscv-probe.

Change-Id: I2e9e0c94e6518f63ade7680a3ce68bacfae219d4
Signed-off-by: Xiang Wang <wxjstz@126.com>
Reviewed-on: https://review.coreboot.org/28569
Reviewed-by: Philipp Hug <philipp@hug.cx>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Xiang Wang 2018-09-11 15:53:36 +08:00 committed by Patrick Georgi
parent a08475e9ab
commit 4356e09235
3 changed files with 355 additions and 0 deletions

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@ -54,6 +54,7 @@ bootblock-y += mcall.c
bootblock-y += virtual_memory.c bootblock-y += virtual_memory.c
bootblock-y += boot.c bootblock-y += boot.c
bootblock-y += misc.c bootblock-y += misc.c
bootblock-y += pmp.c
bootblock-y += \ bootblock-y += \
$(top)/src/lib/memchr.c \ $(top)/src/lib/memchr.c \
$(top)/src/lib/memcmp.c \ $(top)/src/lib/memcmp.c \
@ -82,6 +83,7 @@ ifeq ($(CONFIG_ARCH_ROMSTAGE_RISCV),y)
romstage-y += boot.c romstage-y += boot.c
romstage-y += stages.c romstage-y += stages.c
romstage-y += misc.c romstage-y += misc.c
romstage-y += pmp.c
romstage-y += \ romstage-y += \
$(top)/src/lib/memchr.c \ $(top)/src/lib/memchr.c \
$(top)/src/lib/memcmp.c \ $(top)/src/lib/memcmp.c \
@ -120,6 +122,7 @@ ramstage-y += misc.c
ramstage-y += boot.c ramstage-y += boot.c
ramstage-y += tables.c ramstage-y += tables.c
ramstage-y += payload.S ramstage-y += payload.S
ramstage-y += pmp.c
ramstage-y += \ ramstage-y += \
$(top)/src/lib/memchr.c \ $(top)/src/lib/memchr.c \
$(top)/src/lib/memcmp.c \ $(top)/src/lib/memcmp.c \

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@ -0,0 +1,31 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2018 HardenedLinux
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __RISCV_PMP_H__
#define __RISCV_PMP_H__
/*
* this function needs to be implemented by a specific SoC.
* return number of PMP entries for current hart
*/
extern int pmp_entries_num(void);
/* reset PMP setting */
void reset_pmp(void);
/* set up PMP record */
void setup_pmp(uintptr_t base, uintptr_t size, uintptr_t flags);
#endif /* __RISCV_PMP_H__ */

321
src/arch/riscv/pmp.c Normal file
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@ -0,0 +1,321 @@
/*
* This file is part of the coreboot project.
*
* Copyright (C) 2018 HardenedLinux
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <arch/encoding.h>
#include <stdint.h>
#include <arch/pmp.h>
#include <console/console.h>
#include <commonlib/helpers.h>
#define GRANULE (1 << PMP_SHIFT)
/*
* This structure is used to temporarily record PMP
* configuration information.
*/
typedef struct {
/* used to record the value of pmpcfg[i] */
uintptr_t cfg;
/*
* When generating a TOR type configuration,
* the previous entry needs to record the starting address.
* used to record the value of pmpaddr[i - 1]
*/
uintptr_t previous_address;
/* used to record the value of pmpaddr[i] */
uintptr_t address;
} pmpcfg_t;
/* This variable is used to record which entries have been used. */
static uintptr_t pmp_entry_used_mask;
/* helper function used to read pmpcfg[idx] */
static uintptr_t read_pmpcfg(int idx)
{
#if __riscv_xlen == 32
int shift = 8 * (idx & 3);
switch (idx >> 2) {
case 0:
return (read_csr(pmpcfg0) >> shift) & 0xff;
case 1:
return (read_csr(pmpcfg1) >> shift) & 0xff;
case 2:
return (read_csr(pmpcfg2) >> shift) & 0xff;
case 3:
return (read_csr(pmpcfg3) >> shift) & 0xff;
}
#elif __riscv_xlen == 64
int shift = 8 * (idx & 7);
switch (idx >> 3) {
case 0:
return (read_csr(pmpcfg0) >> shift) & 0xff;
case 1:
return (read_csr(pmpcfg2) >> shift) & 0xff;
}
#endif
return -1;
}
/* helper function used to write pmpcfg[idx] */
static void write_pmpcfg(int idx, uintptr_t cfg)
{
uintptr_t old;
uintptr_t new;
#if __riscv_xlen == 32
int shift = 8 * (idx & 3);
switch (idx >> 2) {
case 0:
old = read_csr(pmpcfg0);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg0, new);
break;
case 1:
old = read_csr(pmpcfg1);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg1, new);
break;
case 2:
old = read_csr(pmpcfg2);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg2, new);
break;
case 3:
old = read_csr(pmpcfg3);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg3, new);
break;
}
#elif __riscv_xlen == 64
int shift = 8 * (idx & 7);
switch (idx >> 3) {
case 0:
old = read_csr(pmpcfg0);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg0, new);
break;
case 1:
old = read_csr(pmpcfg2);
new = (old & ~((uintptr_t)0xff << shift))
| ((cfg & 0xff) << shift);
write_csr(pmpcfg2, new);
break;
}
#endif
if (read_pmpcfg(idx) != cfg)
die("write pmpcfg failure!");
}
/* helper function used to read pmpaddr[idx] */
static uintptr_t read_pmpaddr(int idx)
{
switch (idx) {
case 0:
return read_csr(pmpaddr0);
case 1:
return read_csr(pmpaddr1);
case 2:
return read_csr(pmpaddr2);
case 3:
return read_csr(pmpaddr3);
case 4:
return read_csr(pmpaddr4);
case 5:
return read_csr(pmpaddr5);
case 6:
return read_csr(pmpaddr6);
case 7:
return read_csr(pmpaddr7);
case 8:
return read_csr(pmpaddr8);
case 9:
return read_csr(pmpaddr9);
case 10:
return read_csr(pmpaddr10);
case 11:
return read_csr(pmpaddr11);
case 12:
return read_csr(pmpaddr12);
case 13:
return read_csr(pmpaddr13);
case 14:
return read_csr(pmpaddr14);
case 15:
return read_csr(pmpaddr15);
}
return -1;
}
/* helper function used to write pmpaddr[idx] */
static void write_pmpaddr(int idx, uintptr_t val)
{
switch (idx) {
case 0:
write_csr(pmpaddr0, val);
break;
case 1:
write_csr(pmpaddr1, val);
break;
case 2:
write_csr(pmpaddr2, val);
break;
case 3:
write_csr(pmpaddr3, val);
break;
case 4:
write_csr(pmpaddr4, val);
break;
case 5:
write_csr(pmpaddr5, val);
break;
case 6:
write_csr(pmpaddr6, val);
break;
case 7:
write_csr(pmpaddr7, val);
break;
case 8:
write_csr(pmpaddr8, val);
break;
case 9:
write_csr(pmpaddr9, val);
break;
case 10:
write_csr(pmpaddr10, val);
break;
case 11:
write_csr(pmpaddr11, val);
break;
case 12:
write_csr(pmpaddr12, val);
break;
case 13:
write_csr(pmpaddr13, val);
break;
case 14:
write_csr(pmpaddr14, val);
break;
case 15:
write_csr(pmpaddr15, val);
break;
}
if (read_pmpaddr(idx) != val)
die("write pmpaddr failure");
}
/* Generate a PMP configuration of type NA4/NAPOT */
static pmpcfg_t generate_pmp_napot(
uintptr_t base, uintptr_t size, uintptr_t flags)
{
pmpcfg_t p;
flags = flags & (PMP_R | PMP_W | PMP_X | PMP_L);
p.cfg = flags | (size > GRANULE ? PMP_NAPOT : PMP_NA4);
p.previous_address = 0;
p.address = (base + (size / 2 - 1)) >> PMP_SHIFT;
return p;
}
/* Generate a PMP configuration of type TOR */
static pmpcfg_t generate_pmp_range(
uintptr_t base, uintptr_t size, uintptr_t flags)
{
pmpcfg_t p;
flags = flags & (PMP_R | PMP_W | PMP_X | PMP_L);
p.cfg = flags | PMP_TOR;
p.previous_address = base >> PMP_SHIFT;
p.address = (base + size) >> PMP_SHIFT;
return p;
}
/* Generate a PMP configuration */
static pmpcfg_t generate_pmp(uintptr_t base, uintptr_t size, uintptr_t flags)
{
if (IS_POWER_OF_2(size) && (size >= 4) && ((base & (size - 1)) == 0))
return generate_pmp_napot(base, size, flags);
else
return generate_pmp_range(base, size, flags);
}
/*
* find empty PMP entry by type
* TOR type configuration requires two consecutive PMP entries,
* others requires one.
*/
static int find_empty_pmp_entry(int is_range)
{
int free_entries = 0;
for (int i = 0; i < pmp_entries_num(); i++) {
if (pmp_entry_used_mask & (1 << i))
free_entries = 0;
else
free_entries++;
if (is_range && (free_entries == 2))
return i;
if (!is_range && (free_entries == 1))
return i;
}
die("Too many PMP configurations, no free entries can be used!");
return -1;
}
/*
* mark PMP entry has be used
* this function need be used with find_entry_pmp_entry
*
* n = find_empty_pmp_entry(is_range)
* ... // PMP set operate
* mask_pmp_entry_used(n);
*/
static void mask_pmp_entry_used(int idx)
{
pmp_entry_used_mask |= 1 << idx;
}
/* reset PMP setting */
void reset_pmp(void)
{
for (int i = 0; i < pmp_entries_num(); i++) {
if (read_pmpcfg(i) & PMP_L)
die("Some PMP configurations are locked "
"and cannot be reset!");
write_pmpcfg(i, 0);
write_pmpaddr(i, 0);
}
}
/* set up PMP record */
void setup_pmp(uintptr_t base, uintptr_t size, uintptr_t flags)
{
pmpcfg_t p;
int is_range, n;
p = generate_pmp(base, size, flags);
is_range = ((p.cfg & PMP_A) == PMP_TOR);
n = find_empty_pmp_entry(is_range);
write_pmpaddr(n, p.address);
if (is_range)
write_pmpaddr(n - 1, p.previous_address);
write_pmpcfg(n, p.cfg);
mask_pmp_entry_used(n);
if (is_range)
mask_pmp_entry_used(n - 1);
}