riscv64-linux-gnu-gcc -MMD -MP -MF arch/riscv/.early_printk.o.d -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wdeclaration-after-statement -Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc -fno-builtin -fno-common -Werror -Wredundant-decls -Wno-pointer-arith -Wvla -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute -g -mabi=lp64  -I./include -I./arch/riscv/include -march=rv64gc -mstrict-align -mcmodel=medany   -c arch/riscv/early_printk.c -o arch/riscv/early_printk.o
  arch/riscv/early_printk.c:18:2: error: #error "early_*() can be called from head.S with MMU-off"
     18 | #error "early_*() can be called from head.S with MMU-off"
        |  ^~~~~

  $ riscv64-linux-gnu-gcc --version
  riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110

The binary is otherwise correct, so remove the incorrect check.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Bob Eshleman <bobbyeshleman@gmail.com>
CC: Alistair Francis <alistair.francis@wdc.com>
CC: Connor Davis <connojdavis@gmail.com>

I was honestly hoping to leave this to some poor sole in the future.

But the irony of this check, after all the argument it caused, breaking the
very case it was trying to enforce, speaks volumes.
---
 xen/arch/riscv/early_printk.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/xen/arch/riscv/early_printk.c b/xen/arch/riscv/early_printk.c
index dfe4ad77e25d..b66a11f1bc1a 100644
--- a/xen/arch/riscv/early_printk.c
+++ b/xen/arch/riscv/early_printk.c
@@ -7,17 +7,6 @@
 #include <asm/early_printk.h>
 #include <asm/sbi.h>
 
-/*
- * When the MMU is off during early boot, any C function called has to
- * use PC-relative rather than absolute address because the physical address
- * may not match the virtual address.
- *
- * To guarantee PC-relative address cmodel=medany should be used
- */
-#ifndef __riscv_cmodel_medany
-#error "early_*() can be called from head.S with MMU-off"
-#endif
-
 /*
  * TODO:
  *   sbi_console_putchar is already planned for deprecation
-- 
2.30.2

On 15.03.2023 19:51, Andrew Cooper wrote:
>   riscv64-linux-gnu-gcc -MMD -MP -MF arch/riscv/.early_printk.o.d -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wdeclaration-after-statement -Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc -fno-builtin -fno-common -Werror -Wredundant-decls -Wno-pointer-arith -Wvla -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute -g -mabi=lp64  -I./include -I./arch/riscv/include -march=rv64gc -mstrict-align -mcmodel=medany   -c arch/riscv/early_printk.c -o arch/riscv/early_printk.o
>   arch/riscv/early_printk.c:18:2: error: #error "early_*() can be called from head.S with MMU-off"
>      18 | #error "early_*() can be called from head.S with MMU-off"
>         |  ^~~~~
> 
>   $ riscv64-linux-gnu-gcc --version
>   riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110
> 
> The binary is otherwise correct, so remove the incorrect check.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

I'm with Julien here - this needs further explaining: The compiler (even 8.2)
clearly provides this definition with the given set of command line options,
as supported by trying it out om godbolt. So there must be more to this -
could be a bad patch in Debian's build, could be some odd interaction of
command line options which for whatever reason only triggers with certain
builds, or about anything else.

Jan

On Wed, 15 Mar 2023 at 11:52, Andrew Cooper <andrew.cooper3@citrix.com>
wrote:

>   riscv64-linux-gnu-gcc -MMD -MP -MF arch/riscv/.early_printk.o.d
> -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
> -Wdeclaration-after-statement -Wno-unused-but-set-variable
> -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc
> -fno-builtin -fno-common -Werror -Wredundant-decls -Wno-pointer-arith -Wvla
> -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute
> -g -mabi=lp64  -I./include -I./arch/riscv/include -march=rv64gc
> -mstrict-align -mcmodel=medany   -c arch/riscv/early_printk.c -o
> arch/riscv/early_printk.o
>   arch/riscv/early_printk.c:18:2: error: #error "early_*() can be called
> from head.S with MMU-off"
>      18 | #error "early_*() can be called from head.S with MMU-off"
>         |  ^~~~~
>
>   $ riscv64-linux-gnu-gcc --version
>   riscv64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110
>
> The binary is otherwise correct, so remove the incorrect check.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Bob Eshleman <bobbyeshleman@gmail.com>
> CC: Alistair Francis <alistair.francis@wdc.com>
> CC: Connor Davis <connojdavis@gmail.com>
>
> I was honestly hoping to leave this to some poor sole in the future.
>
> But the irony of this check, after all the argument it caused, breaking the
> very case it was trying to enforce, speaks volumes.


I appreciate you dislike this check. But I think the fact it gets triggered
proved its effectiveness rather than the other way around.

From a brief look online, the define is meant to be present with medany. So
I think some digging would be worth here as this may indicate another
latent issue either on the command line or the compiler.

(I would like to point out that Linux has the exact same check. So why
would it work there but not in Xen?)

Cheers,




> ——
>  xen/arch/riscv/early_printk.c | 11 -----------
>  1 file changed, 11 deletions(-)
>
> diff --git a/xen/arch/riscv/early_printk.c b/xen/arch/riscv/early_printk.c
> index dfe4ad77e25d..b66a11f1bc1a 100644
> --- a/xen/arch/riscv/early_printk.c
> +++ b/xen/arch/riscv/early_printk.c
> @@ -7,17 +7,6 @@
>  #include <asm/early_printk.h>
>  #include <asm/sbi.h>
>
> -/*
> - * When the MMU is off during early boot, any C function called has to
> - * use PC-relative rather than absolute address because the physical
> address
> - * may not match the virtual address.
> - *
> - * To guarantee PC-relative address cmodel=medany should be used
> - */
> -#ifndef __riscv_cmodel_medany
> -#error "early_*() can be called from head.S with MMU-off"
> -#endif
> -
>  /*
>   * TODO:
>   *   sbi_console_putchar is already planned for deprecation
> --
> 2.30.2
>
>
>