From: Michael Ellerman mpe@ellerman.id.au
[ Upstream commit b56d55a5aa4aa9fc166595a7feb57f153ef7b555 ]
The flags argument to plpar_pte_protect() (aka. H_PROTECT), includes the key in bits 9-13, but currently we always set those bits to zero.
In the past that hasn't been a problem because we always used key 0 for the kernel, and updateboltedpp() is only used for kernel mappings.
However since commit d94b827e89dc ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation") we are now inadvertently changing the key (to zero) when we call plpar_pte_protect().
That hasn't broken anything because updateboltedpp() is only used for STRICT_KERNEL_RWX, which is currently disabled on 64s due to other bugs.
But we want to fix that, so first we need to pass the key correctly to plpar_pte_protect(). We can't pass our newpp value directly in, we have to convert it into the form expected by the hcall.
The hcall we're using here is H_PROTECT, which is specified in section 14.5.4.1.6 of LoPAPR v1.1.
It takes a `flags` parameter, and the description for flags says:
* flags: AVPN, pp0, pp1, pp2, key0-key4, n, and for the CMO option: CMO Option flags as defined in Table 189‚
If you then go to the start of the parent section, 14.5.4.1, on page 405, it says:
Register Linkage (For hcall() tokens 0x04 - 0x18) * On Call * R3 function call token * R4 flags (see Table 178‚ “Page Frame Table Access flags field definition‚” on page 401)
Then you have to go to section 14.5.3, and on page 394 there is a list of hcalls and their tokens (table 176), and there you can see that H_PROTECT == 0x18.
Finally you can look at table 178, on page 401, where it specifies the layout of the bits for the key:
Bit Function ----------------- 50-54 | key0-key4
Those are big-endian bit numbers, converting to normal bit numbers you get bits 9-13, or 0x3e00.
In the kernel we have:
#define HPTE_R_KEY_HI ASM_CONST(0x3000000000000000) #define HPTE_R_KEY_LO ASM_CONST(0x0000000000000e00)
So the LO bits of newpp are already in the right place, and the HI bits need to be shifted down by 48.
Fixes: d94b827e89dc ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation") Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20210331003845.216246-2-mpe@ellerman.id.au Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/platforms/pseries/lpar.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 3805519a6469..cd38bd421f38 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -977,11 +977,13 @@ static void pSeries_lpar_hpte_updateboltedpp(unsigned long newpp, slot = pSeries_lpar_hpte_find(vpn, psize, ssize); BUG_ON(slot == -1);
- flags = newpp & 7; + flags = newpp & (HPTE_R_PP | HPTE_R_N); if (mmu_has_feature(MMU_FTR_KERNEL_RO)) /* Move pp0 into bit 8 (IBM 55) */ flags |= (newpp & HPTE_R_PP0) >> 55;
+ flags |= ((newpp & HPTE_R_KEY_HI) >> 48) | (newpp & HPTE_R_KEY_LO); + lpar_rc = plpar_pte_protect(flags, slot, 0);
BUG_ON(lpar_rc != H_SUCCESS);